Entity

Time filter

Source Type


Lin X.,Harbin Institute of Technology | He Q.,Harbin Institute of Technology | Li J.,CAS Beijing National Laboratory for Molecular
Chemical Society Reviews | Year: 2012

Confined surface gradients consisting of polymer brushes have great potential in various applications such as microfluidic devices, sensors, and biophysical research. Among the available fabrication approaches, nanolithographies combined with self-assembled monolayers and surface-initiated polymerization have became powerful tools to engineer confined gradients or predefined complex gradients on the nanometre size. In this tutorial review, we mainly highlight the research progress of the fabrication of confined polymer brush gradients by using electron beam, laser, and probe-based nanolithographies and the physical base for these approaches. The application of these polymer brush gradients in biomedical research is also addressed. © The Royal Society of Chemistry 2012.


Zhu Y.,CAS Suzhou Institute of Nano Technology and Nano Bionics | Zhu Y.,University of Chinese Academy of Sciences | Wang D.,CAS Suzhou Institute of Nano Technology and Nano Bionics | Jiang L.,CAS Beijing National Laboratory for Molecular | Jin J.,CAS Suzhou Institute of Nano Technology and Nano Bionics
NPG Asia Materials | Year: 2014

The separation of oily wastewater, especially emulsified oil/water mixtures, is a worldwide challenge because of the large amount of oily wastewater produced in many industrial processes and daily life. For the treatment of oily wastewater, membrane technology is considered the most efficient method because of its high separation efficiency and relatively simple operational process. In this short review, the recent development of advanced filtration membranes for emulsified oil/water mixture separation is presented. We provide an overview on both traditional filtration membranes, including polymer-dominated and ceramic-based filtration membranes, and recently developed nanomaterial-based functional filtration membranes, especially one-dimensional nanomaterials, for effectively treating emulsified oil/water mixtures. The liquid flux and antifouling property, which are the most important factors for membrane performance evaluation, are described for different types of membranes. Conclusions and perspectives concerning the future development of filtration membranes are also provided. © 2014 Nature Publishing Group All rights reserved.


Liu W.,CAS Beijing National Laboratory for Molecular
Physical Chemistry Chemical Physics | Year: 2012

Given the remarkable advances in relativistic quantum chemistry, some conceptual aspects still remain to be addressed. Among others, the role of negative energy states (NES) in electron correlation and other properties requires most attention. Based on critical assessments of the configuration space (CS), no-photon (and no-time) Fock space (FS) and quantum electrodynamics (QED) approaches, it is concluded that only QED provides the correct prescription for the contributions of NES to correlation, while both CS and FS give rise to wrong results. This essentially means that one should work either with the no-pair approximation (which has an intrinsic error of order (Zα) 3) or with QED. Whether a consistent relativistic many-electron theory does exist in between remains an open question. Even under the no-pair approximation, there still exists an issue arising from that the no-pair Hamiltonian is incompatible with explicitly correlated methods. It turns out that this can nicely be resolved by introducing the concept of extended no-pair projection. Apart from these take-home messages, other immediate prospects of relativistic quantum chemistry are also highlighted for guiding future developments and applications.


Zhang W.-S.,CAS Beijing National Laboratory for Molecular
Thermochimica Acta | Year: 2010

A heat-flow calorimeter was designed and built. Its measurements are 26 cm × 26 cm × 26 cm (17.6 dm3). 18,796 thermocouples are used to measure the heat-flow from the vessel walls to the outer walls, for which temperature is controlled within 0.01 °C from 0 to 100 °C by a refrigerating/heating circulator. Homogeneity of temperature in the measuring vessel is improved by a fan with constant power. The calibration was performed with an electric heater, with input power up to 50 W. The device constant is 5.8954 ± 0.0025 W V-1; the time constant is 501.7 ± 3.2 s; the uncertainty is 0.6% at 2 W to 0.06% at 50 W. Nonlinearity of this calorimeter is analyzed. The calorimeter can be utilized for studies of kinetics and thermodynamics of physical, chemical and biological systems of decimeter-size. A Sony 26650 Li-ion rechargeable battery was tested with this device during charging and discharging, and an electrolytic cell with Pd-D2O was also tested with this device. © 2009 Elsevier B.V. All rights reserved.


Jiang H.,CAS Beijing National Laboratory for Molecular | Rinke P.,Fritz Haber Institute | Scheffler M.,Fritz Haber Institute
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

A first-principles understanding of the electronic properties of f-electron systems is currently regarded as a great challenge in condensed-matter physics because of the difficulty in treating both localized and itinerant states on the same footing by the current theoretical approaches, most notably density-functional theory (DFT) in the local-density or generalized gradient approximation (LDA/GGA). Lanthanide sesquioxides (Ln 2O 3) are typical f-electron systems for which the highly localized f states play an important role in determining their chemical and physical properties. In this paper, we present a systematic investigation of the performance of many-body perturbation theory in the GW approach for the electronic structure of the whole Ln 2O 3 series. To overcome the major failure of LDA/GGA, the traditional starting point for GW, for f-electron systems, we base our GW calculations on Hubbard U corrected LDA calculations (LDA+U). The influence of the crystal structure, the magnetic ordering, and the existence of metastable states on the electronic band structures are studied at both the LDA+U and the GW level. The evolution of the band structure with increasing number of f electrons is shown to be the origin for the characteristic structure of the band gap across the lanthanide sesquioxide series. A comparison is then made to dynamical mean-field theory (DMFT) combined with LDA or hybrid functionals to elucidate the pros and cons of these different approaches. © 2012 American Physical Society.


Cheng P.,CAS Beijing National Laboratory for Molecular | Cheng P.,University of Chinese Academy of Sciences | Zhan X.,Peking University
Chemical Society Reviews | Year: 2016

Organic solar cells (OSCs) present some advantages, such as simple preparation, light weight, low cost and large-area flexible fabrication, and have attracted much attention in recent years. Although the power conversion efficiencies have exceeded 10%, the inferior device stability still remains a great challenge. In this review, we summarize the factors limiting the stability of OSCs, such as metastable morphology, diffusion of electrodes and buffer layers, oxygen and water, irradiation, heating and mechanical stress, and survey recent progress in strategies to increase the stability of OSCs, such as material design, device engineering of active layers, employing inverted geometry, optimizing buffer layers, using stable electrodes and encapsulation. Some research areas of device stability that may deserve further attention are also discussed to help readers understand the challenges and opportunities in achieving high efficiency and high stability of OSCs towards future industrial manufacture. © 2016 The Royal Society of Chemistry.


Lang X.,Nanyang Technological University | Zhao J.,CAS Beijing National Laboratory for Molecular | Chen X.,Nanyang Technological University
Chemical Society Reviews | Year: 2016

Visible-light photoredox catalysis has been experiencing a renaissance in response to topical interest in renewable energy and green chemistry. The latest progress in this area indicates that cooperation between photoredox catalysis and other domains of catalysis could provide effective results. Thus, we advance the concept of cooperative photoredox catalysis for organic transformations. It is important to note that this concept can bridge the gap between visible-light photoredox catalysis and other types of redox catalysis such as transition-metal catalysis, biocatalysis or electrocatalysis. In doing so, one can take advantage of the best of both worlds in establishing organic synthesis with visible-light-induced redox reaction as a crucial step. © 2016 The Royal Society of Chemistry.


Yi Z.,Huazhong University of Science and Technology | Wang S.,Huazhong University of Science and Technology | Liu Y.,CAS Beijing National Laboratory for Molecular
Advanced Materials | Year: 2015

Since the report of the first diketopyrrolopyrrole (DPP)-based polymer semiconductor, such polymers have received considerable attention as a promising candidate for high-performance polymer semiconductors in organic thin-film transistors (OTFTs). This Progress Report summarizes the advances in the molecular design of high-mobility DPP-based polymers reported in the last few years, especially focusing on the molecular design of these polymers in respect of tuning the backbone and side chains, and discussing the influences of structural modification of the backbone and side chains on the properties and device performance of corresponding DPP-based polymers. This provides insights for the development of new and high-mobility polymer semiconductors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zhang L.S.,CAS Beijing National Laboratory for Molecular
Nanoscale | Year: 2011

Reduced graphene oxide (RGO) was synthesized under H(2)/Ar treatment from 100 °C to 900 °C. RGO-300 shows excellent sensitivity to H(2) and a dual sensing mode was observed. The balance between the chemical adsorption capacity and electronic conductivity, and the dominance of either electrons or holes are the key factors.


Yan N.,Ecole Polytechnique Federale de Lausanne | Yuan,Ecole Polytechnique Federale de Lausanne | Dykeman R.,Ecole Polytechnique Federale de Lausanne | Kou Y.,CAS Beijing National Laboratory for Molecular | Dyson P.J.,Ecole Polytechnique Federale de Lausanne
Angewandte Chemie - International Edition | Year: 2010

Oxy-gone in a tandem: A catalytic system composed of metal nanoparticles (NPs) and a functionalized Brensted acidic ionic liquid (IL), both of which are immobilized in a nonfunctionalized IL, is highly efficient in upgrading lignin-derived phenolic compounds into alkanes; the hydrogenation and dehydration reactions take place in tandem. Figure Presented © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.


Lin Y.,CAS Beijing National Laboratory for Molecular | Lin Y.,University of Chinese Academy of Sciences | Zhan X.,Peking University
Materials Horizons | Year: 2014

Although fullerenes and their derivatives, such as PCBM, have been the dominant electron-acceptor materials in organic photovoltaic cells (OPVs), they suffer from some disadvantages, such as weak absorption in the visible spectral region, limited spectral breadth and difficulty in variably tuning the band gap. It is necessary to explore non-fullerene electron acceptors that will not only retain the favorable electron-accepting and transporting properties of fullerenes but also overcome their insufficiencies. After a decade of mediocrity, non-fullerene acceptors are undergoing rapid development and are emerging as a hot area of focus in the field of organic semiconductors. Solution-processed bulk heterojunction (BHJ) OPVs based on non-fullerene acceptors have shown encouraging power conversion efficiencies of over 4%. This article reviews recent developments in several classes of solution-processable non-fullerene acceptors for BHJ OPVs. The remaining problems and challenges along with the key research directions in the near future are discussed. © The Royal Society of Chemistry 2014.


Usharani D.,Hebrew University of Jerusalem | Lai W.,Renmin University of China | Li C.,CAS Fujian Institute of Research on the Structure of Matter | Li C.,Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry | And 3 more authors.
Chemical Society Reviews | Year: 2014

This is a tutorial on the usage of valence bond (VB) diagrams for understanding chemical reactivity in general, and hydrogen atom transfer (HAT) reactivity in particular. The tutorial instructs the reader how to construct the VB diagrams and how to estimate HAT barriers from raw data, starting with the simplest reaction H + H2 and going all the way to HAT in the enzyme cytochrome P450. Other reactions are treated as well, and some unifying principles are outlined. The tutorial projects the unity of reactivity treatments, following Coulson's dictum "give me insight, not numbers", albeit with its modern twist: giving numbers and insight. This journal is © the Partner Organisations 2014.


Chen X.,University of Missouri - Kansas City | Liu L.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Huang F.,CAS Beijing National Laboratory for Molecular | Huang F.,CAS Shanghai Institute of Ceramics
Chemical Society Reviews | Year: 2015

In the past few decades, there has been a wide research interest in titanium dioxide (TiO2) nanomaterials due to their applications in photocatalytic hydrogen generation and environmental pollution removal. Improving the optical absorption properties of TiO2 nanomaterials has been successfully demonstrated to enhance their photocatalytic activities, especially in the report of black TiO2 nanoparticles. The recent progress in the investigation of black TiO2 nanomaterials has been reviewed here, and special emphasis has been given on their fabrication methods along with their various chemical/physical properties and applications. This journal is © The Royal Society of Chemistry.


Liu K.,Beihang University | Jiang L.,Beihang University | Jiang L.,CAS Beijing National Laboratory for Molecular
ACS Nano | Year: 2011

Nature is a school for human beings. Learning from nature has long been a source of bioinspiration for scientists and engineers. Multiscale structures are characteristic for biological materials, exhibiting inherent multifunctional integration. Optimized biological solutions provide inspiration for scientists and engineers to design and to fabricate multiscale structured materials for multifunctional integration. © 2011 American Chemical Society.


Chen C.-F.,CAS Beijing National Laboratory for Molecular
Chemical Communications | Year: 2011

The development of new classes of macrocyclic hosts has always been one of the most important topics in supramolecular chemistry. During the past several years, based on the triptycene with unique three-dimensional rigid structure, several different kinds of novel triptycene-derived hosts including triptycene-derived cylindrical macrotricyclic polyether, triptycene-derived tris(crown ether)s, triptycene-derived molecular tweezers, triptycene-derived calixarenes, triptycene-derived heterocalixarenes, triptycene-derived tetralactam macrocycles and molecular cage have been designed and synthesized. Then, by exploring the applications of some of the triptycene derived hosts in molecular recognition and molecular assemblies, a series of new supramolecular systems with specific structures and properties have been developed. This feature article highlights our recent advances in the synthesis of triptycene-derived hosts and their applications in supramolecular chemistry. © 2011 The Royal Society of Chemistry.


Tao M.,Ningbo Institute of Materials Technology and Engineering | Xue L.,Ningbo Institute of Materials Technology and Engineering | Liu F.,Ningbo Institute of Materials Technology and Engineering | Jiang L.,CAS Beijing National Laboratory for Molecular
Advanced Materials | Year: 2014

A superamphiphilic poly(vinylidene fluoride) (PVDF) membrane with superoleophobicity under water and superhydrophobicity under oil is successfully prepared. Due to the switchable transport performance, the membrane is applicable to the separation of various oil-in-water and water-in-oil emulsions with a droplet size greater than 20 nm, and shows superior permeability and antifouling properties, as well as a high separation efficiency. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Wang F.,North China Electrical Power University | Tan Z.,North China Electrical Power University | Li Y.,CAS Beijing National Laboratory for Molecular | Li Y.,Soochow University of China
Energy and Environmental Science | Year: 2015

The interfaces between the electrodes and the photoactive layer significantly influence the efficiency and stability of polymer solar cells (PSCs). By choosing suitable interfacial materials, the energetic barrier height at the interface could be reduced to form an ohmic contact with less series resistance, inducing high charge collection efficiency of the corresponding electrodes for holes or electrons. Solution-processable metal compounds, especially metal oxides and transition metal chelates, have the advantages of high charge carrier mobility, suitable work function, low cost, and high environmental stability, which make them attractive for applications as cathode and anode interfacial materials for efficient and stable PSCs. In this paper, we reviewed the recent progress on solution processable metal oxides and metal chelates as buffer layers in conventional and inverted PSCs. In the introduction section, we introduced the operating principles of conventional and inverted PSCs, followed by introducing the energy levels, optical properties, processing methods and characterization techniques of the buffer layers. In the second and third parts, we reviewed recent progress in materials for both anode and cathode buffer layers. Finally, we drew a conclusion and gave a perspective. We believe that solution-processable metal oxides and metal chelates will play a key role as buffer layers in the future fabrication of large area and flexible PSCs with high performance and long term stability. © 2015 The Royal Society of Chemistry.


Zhang X.,CAS Technical Institute of Physics and Chemistry | Zeng Y.,CAS Technical Institute of Physics and Chemistry | Yu T.,CAS Technical Institute of Physics and Chemistry | Chen J.,CAS Technical Institute of Physics and Chemistry | And 2 more authors.
Journal of Physical Chemistry Letters | Year: 2014

Dendrimers are regularly and hierarchically branched synthetic macromolecules with numerous chain ends all emanating from a single core, which makes them attractive candidates for energy conversion applications. During photosynthesis and photocatalysis, photoinduced electron transfer and energy transfer are the main processes involved. Studies on these processes in dendritic systems are critical for the future applications of dendrimers in photochemical energy conversion and other optoelectronic devices. In this Perspective, the recent advances of photofunctional dendrimers in energy conversion based on light-harvesting systems, solar cells, and photochemical production of hydrogen will be discussed. The electron-transfer and energy-transfer characteristics in light-harvesting photofunctional dendrimers and the regulation of the electron-transfer process and the stabilization of the charge separation state in hydrogen photoproduction are emphasized. © 2014 American Chemical Society.


Qi W.,Qufu Normal University | Duan L.,Nuclear Technology | Li J.,CAS Beijing National Laboratory for Molecular
Soft Matter | Year: 2011

The layer-by-layer (LbL) technique has been widely used to construct different types of microcapsules based on the electrostatic interaction between charged polymers and proteins. However, in this review, we will mainly focus on the fabrication of microcapsules by using a covalent cross-linking method. The structure and properties of the assembled microcapsules are described and their potential applications in glucose-sensing and glucose-sensitive drug delivery are introduced. © 2011 The Royal Society of Chemistry.


Liu Q.,Tsinghua University | Liu Q.,CAS Beijing National Laboratory for Molecular
Electrochimica Acta | Year: 2014

Mg salts [Mg(NO3)2·6H2O]-doped TiO2 electrodes prepared well-optimized by the hydrothermal method. To prepare the working electrode, the TiO2 or Mg-doped TiO 2 slurry was coated onto the fluorine-doped tin oxide glass substrate by the doctor blade method and was then sintered at 450 °C. X-ray photoelectron spectroscopy (XPS) data indicated that the doped Mg ions exist in form of Mg2+, which can play a role as e- or h+ traps and reduce e-/h+ pair recombination rate, The Mott-Schottky plot indicates that the Mg-doped TiO2 photoanode shifts the flat band potential positively. The positive shift of the flat band potential improves the driving force of injected electrons from the LUMO of the dye to the conduction band of TiO2. This study show a photovoltaic efficiency of 7.12%, which is higher than that of the undoped TiO2 thin film (5.62%) and increase short-current by 26.7% from 14.9 mA to 19.1 mA. © 2014 Elsevier Ltd.


Wang J.,Beihang University | Lin L.,CAS Beijing National Laboratory for Molecular | Cheng Q.,Beihang University | Jiang L.,Beihang University
Angewandte Chemie - International Edition | Year: 2012

Inspired by nacre, a layered poly(N-isopropylacrylamide)-clay nanocomposite hydrogel was successfully fabricated by combination of vacuum-filtration self-assembly and photo-initiated in situ polymerization. This bio-inspired layered nanocomposite hydrogel shows excellent mechanical properties, which can rival some biological soft tissues (see picture). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Yan J.-J.,Anhui University of Science and Technology | Wang D.,Anhui University of Science and Technology | Wu D.-C.,CAS Beijing National Laboratory for Molecular | You Y.-Z.,Anhui University of Science and Technology
Chemical Communications | Year: 2013

Sequence-ordered polymers can be simply prepared in one pot via sequential monomer addition. © 2013 The Royal Society of Chemistry.


Jiang H.,CAS Beijing National Laboratory for Molecular
Journal of Chemical Physics | Year: 2011

Early transition metal dichalcogenides (TMDC), characterized by their quasi-two-dimensional layered structure, have attracted intensive interest due to their versatile chemical and physical properties, but a comprehensive understanding of their structural and electronic properties from a first-principles point of view is still lacking. In this work, four simple TMDC materials, MX2 (M=Zr and Hf, X=S and Se), are investigated by the Kohn-Sham density functional theory (KS-DFT) with different local or semilocal exchange-correlation (xc) functionals and many-body perturbation theory in the GW approximation. Although the widely used Perdew-Burke-Ernzelhof (PBE) generalized gradient approximation (GGA) xc functional overestimates the interlayer distance dramatically, two newly developed GGA functionals, PBE-for-solids (PBEsol) and Wu-Cohen 2006 (WC06), can reproduce experimental crystal structures of these TMDC materials very well. The GW method, currently the most accurate first-principles approach for electronic band structures of extended systems, gives the fundamental band gaps of all these materials in good agreement with the experimental values obtained from optical absorption. The minimal direct gaps from GW are systematically larger than those measured from thermoreflectance by about 0.1-0.3 eV, implying that excitonic effects may be stronger than previously estimated. The calculated density of states from GW quasi-particle band energies agrees very well with photo-emission spectroscopy data. Ionization potentials of these materials are also computed by combining PBE calculations based on the slab model and GW quasi-particle corrections. The calculated absolute band energies with respect to the vacuum level indicate that that ZrS2 and HfS2, although having suitable band gaps for visible light absorption, cannot be used for overall water splitting as a result of mismatch of the conduction band minimum with the redox potential of H+/H2. © 2011 American Institute of Physics.


Xu B.,Nankai University | Zhu S.-F.,Nankai University | Zhang Z.-C.,Nankai University | Yu Z.-X.,CAS Beijing National Laboratory for Molecular | And 2 more authors.
Chemical Science | Year: 2014

The first highly enantioselective S-H bond insertion reaction was developed by cooperative catalysis of dirhodium(ii) carboxylates and chiral spiro phosphoric acids (SPAs) under mild and neutral reaction conditions with fast reaction rates, high yields (77-97% yields), and excellent enantioselectivities (up to 98% ee). The catalytic S-H bond insertion reaction provides a highly efficient method for the synthesis of chiral sulfur-containing compounds and advances the synthesis of a chiral sulfur-containing drug (S)-Eflucimibe. A systematic 31P NMR study revealed that no ligand exchange between dirhodium(ii) carboxylates and SPAs occurred in the reaction. The distinct behaviors of cooperative catalysts Rh2(TPA)4/(R)-1a and the prepared complex Rh2(R-1a)4 observed by in situ FT-IR spectroscopy excluded the feasibility of Rh2(R-SPA)4 being the real catalyst. DFT calculations showed that the activation barrier in the proton shift step became remarkably low as promoted by SPAs. Based on the experimental results and the calculations, the SPA was proposed as a chiral proton shuttle for the proton shift in reaction. Additionally, the single crystal structures of several SPAs were measured and used to rationalize the configurations of the S-H insertion products obtained in the reactions. The rigid and crowded environment around the SPAs ensures the high enantioselectivity in the S-H bond insertion reaction. © 2014 The Royal Society of Chemistry.


Fang X.,CAS Beijing National Laboratory for Molecular | Tan W.,University of Florida | Tan W.,Hunan University
Accounts of Chemical Research | Year: 2010

Molecular medicine is an emerging field focused on understanding the molecular basis of diseases and translating this information into strategies for diagnosis and therapy. This approach could lead to personalized medical treatments. Currently, our ability to understand human diseases at the molecular level is limited by the lack of molecular tools to identify and characterize the distinct molecular features of the disease state, especially for diseases such as cancer. Among the new tools being developed by researchers including chemists, engineers, and other scientists is a new class of nucleic acid probes called aptamers, which are ssDNA/RNA molecules selected to target a wide range of molecules and even cells. In this Account, we will focus on the use of aptamers, generated from cell-based selections, as a novel molecular tool for cancer research. Cancers originate from mutations of human genes. These genetic alterations result in molecular changes to diseased cells, which, in turn, lead to changes in cell morphology and physiology. For decades, clinicians have diagnosed cancers primarily based on the morphology of tumor cells or tissues. However, this method does not always give an accurate diagnosis and does not allow clinicians to effectively assess the complex molecular alterations that are predictive of cancer progression. As genomics and proteomics do not yet allow a full access to this molecular knowledge, aptamer probes represent one effective and practical avenue toward this goal. One special feature of aptamers is that we can isolate them by selection against cancer cells without prior knowledge of the number and arrangement of proteins on the cellular surface. These probes can identify molecular differences between normal and tumor cells and can discriminate among tumor cells of different classifications, at different disease stages, or from different patients. This Account summarizes our recent efforts to develop aptamers through cell-SELEX for the study of cancer and apply those aptamers in cancer diagnosis and therapy. We first discuss how we select aptamers against live cancer cells. We then describe uses of these aptamers. Aptamers can serve as agents for molecular profiling of spedfic cancer types. They can also be used to modify therapeutic reagents to develop targeted cancer therapies. Aptamers are also aiding the discovery of new cancer biomarkers through the recognition of membrane protdn targets. Importantly, we demonstrate how molecular assemblies can integrate the properties of aptamers and, for example, nanoparticles or microfluidic devices, to improve cancer cell enrichment, detection and therapy. Figure Presented. © 2010 American Chemical Society.


Lai W.,Hebrew University of Jerusalem | Lai W.,Renmin University of China | Li C.,Hebrew University of Jerusalem | Chen H.,Hebrew University of Jerusalem | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2012

"Give us insight, not numbers" was Coulson's admonition to theoretical chemists. This Review shows that the valence bond (VB)-model provides insights and some good numbers for one of the fundamental reactions in nature, the hydrogen-atom transfer (HAT). The VB model is applied to over 50 reactions from the simplest H + H 2 process, to P450 hydroxylations and H-transfers among closed-shell molecules; for each system the barriers are estimated from raw data. The model creates a bridge to the Marcus equation and shows that H-atom abstraction by a closed-shell molecule requires a higher barrier owing to the additional promotion energy needed to prepare the abstractor for H-abstraction. Under certain conditions, a closed-shell abstractor can bypass this penalty through a proton-coupled electron transfer (PCET) mechanism. The VB model links the HAT and PCET mechanisms conceptually and shows the consequences that this linking has for H-abstraction reactivity. Give us insight and good numbers: Is it possible to understand one of the fundamental reactions in nature, the hydrogen-atom transfer (HAT), using a single unifying theory? The valence bond diagram model is such a unifying theory. It enables the barriers to be estimated from raw data (see plot), thereby creating a natural bridge to the Marcus equation, addresses the relationships between HAT to proton-coupled electron transfer (PCET), and shows how H-abstractions by closed-shell molecules can occur. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Shuai Z.,Tsinghua University | Peng Q.,CAS Beijing National Laboratory for Molecular
Physics Reports | Year: 2014

Photo- or electro-excited states in polyatomic molecules, aggregates, and conjugated polymers are at the center of organic light-emitting diodes (OLEDs). These can decay radiatively or non-radiatively, determining the luminescence quantum efficiency of molecular materials. According to Kasha's rule, light-emission is dictated by the lowest-lying excited state. For conjugated polymers, the electron correlation effect can lead the lowest-lying excited state to the even-parity 2Ag state which is non-emissive. To understand the nature of the low-lying excited state structure, we developed the density matrix renormalization group (DMRG) theory and its symmetrization scheme for quantum chemistry applied to calculate the excited states structure. We found there are three types of 1Bu/2Ag crossover behaviors: with electron correlation strength U, with bond length alternation, and with conjugation length. These directly influence the light-emitting property.For the electro-excitation, carriers (electron and hole) are injected independently, forming both singlet and triplet excited bound states with statistically 25% and 75% portions, respectively. We found that the exciton formation rate can depend on spin manifold, and for conjugated polymers, the singlet exciton can have larger formation rate leading to the internal electroluminescence quantum efficiency larger than the 25% spin statistical limit. It is originated from the interchain electron correlation as well as intrachain lattice relaxation.For the dipole allowed emissive state, the radiative decay process via either spontaneous emission or stimulated emission can be computed from electronic structure plus vibronic couplings. The challenging issue lies in the non-radiative decay via non-adiabatic coupling and/or spin-orbit coupling. We developed a unified correlation function formalism for the excited state radiative and non-radiative decay rates. We emphasized the low-frequency mode mixing (Duschinsky rotation) effect on the non-radiative decay. We further combined the non-adiabatic coupling and spin-orbit coupling for the triplet state decay (phosphorescence) quantum efficiency. All the formalisms have been developed analytically, which have been applied to optical spectroscopy, aggregation-induced emission phenomena, and polymer photovoltaic property. © 2013 Elsevier B.V.


Liu W.,CAS Beijing National Laboratory for Molecular
Physics Reports | Year: 2014

A quantum mechanical equation Hψ=Eψ is composed of three components, viz., Hamiltonian H, wave function ψ, and property E(λ), each of which is confronted with fundamental issues in the relativistic regime, e.g.,(1) What is the most appropriate relativistic many-body Hamiltonian? How to solve the resulting equation? (2) How does the relativistic wave function behave at the coalescence of two electrons? How to do relativistic explicit correlation? (3) How to formulate relativistic properties properly?, to name just a few. It is shown here that the charge-conjugated contraction of Fermion operators, dictated by the charge conjugation symmetry, allows for a bottom-up construction of a relativistic Hamiltonian that is in line with the principles of quantum electrodynamics (QED). Various approximate but accurate forms of the Hamiltonian can be obtained based entirely on physical arguments. In particular, the exact two-component Hamiltonians can be formulated in a general way to cast electric and magnetic fields, as well as electron self-energy and vacuum polarization, into a unified framework. While such algebraic two-component Hamiltonians are incompatible with explicit correlation, four-component relativistic explicitly correlated approaches can indeed be made fully parallel to the nonrelativistic counterparts by virtue of the 'extended no-pair projection' and the coalescence conditions. These findings open up new avenues for future developments of relativistic molecular quantum mechanics. In particular, 'molecular QED' will soon become an active and exciting field. © 2013 Elsevier B.V.


Jiang H.,CAS Beijing National Laboratory for Molecular
International Journal of Quantum Chemistry | Year: 2015

First-principles treatment of strongly correlated systems is currently regarded as one of greatest challenges in theoretical chemistry and condensed matter physics. While great efforts have been invested to extend current electronic structure theories to treat strong correlation, there is also increasing interest in combining first-principles approaches with model Hamiltonians to take advantage of the best of the two theoretical frameworks. This short review aims at giving an overview of first-principles approaches that are currently used for strongly correlated materials, and remarking on their underlying physical ideas and theoretical limitations. © 2015 Wiley Periodicals, Inc.


Yang X.,CAS Beijing National Laboratory for Molecular
Chemical Communications | Year: 2015

Inspired by the active site structure of monoiron hydrogenase, a series of iron complexes are built using experimentally ready-made acylmethylpyridinol and aliphatic PNP pincer ligands. Density functional theory calculations indicate that the newly designed iron complexes are very promising to catalyze the formation of formic acid from H2 and CO2. © The Royal Society of Chemistry 2015.


Liu J.,CAS Beijing National Laboratory for Molecular
International Journal of Quantum Chemistry | Year: 2015

This article focuses on most recent advances in the linearized semiclassical initial value representation (LSC-IVR)/classical Wigner model that includes quantum effects with classical trajectories and recovers exact thermal correlation functions (of even nonlinear operators, that is, nonlinear functions of position or momentum operators) in the classical, high temperature, and harmonic limits. Two methods for implementing the LSC-IVR/classical Wigner which are in principle feasible to be combined with general force fields or even ab initio electronic structure methods have been reviewed. One is the local Gaussian approximation with the imaginary time path integral approach, the other is the quantum thermal bath method. The article emphasizes on the theory and the algorithms for implementation, while it also covers recent applications and limitations of the LSC-IVR/classical Wigner. © 2015 Wiley Periodicals, Inc.


Diao P.,Beihang University | Liu Z.,CAS Beijing National Laboratory for Molecular
Advanced Materials | Year: 2010

Single-walled carbon nanotubes (SWNTs), as one of the most promising one-dimension nanomaterials due to its unique structure, peculiar chemical, mechanical, thermal, and electronic properties, have long been considered as an important building block to construct ordered alignments. Vertically aligned SWNTs (v-SWNTs) have been successfully prepared by using direct growth and chemical assembly strategies. In this review, we focus explicitly on the v-SWNTs fabricated via chemical assembly strategy. We provide the readers with a full and systematic summary covering the advances in all aspects of this area, including various approaches for the preparation of v-SWNTs using chemical assembly techniques, characterization, assembly kinetics, and electrochemical properties of v-SWNTs. We also review the applications of v-SWNTs in electrochemical and bioelectrochemical sensors, photoelectric conversion, and scanning probe microscopy. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA.


Wang C.,CAS Beijing National Laboratory for Molecular
Synlett | Year: 2013

C-H activation is an emerging powerful strategy to functionalize organic molecules alternative to traditional synthetic tools. Despite being cheap and abundant in the earth's crust, manganese is far less studied within the realm of C-H activation, in particular for C-C bond formation, compared to 'noble' transition metals. Herein, we provide a state-of-the-art review on Mn-mediated C-C bond-forming reactions, both stoichiometric and catalytic, via C-H bond activation. © 2013 Georg Thieme Verlag Stuttgart . New York.


Wang D.-X.,CAS Beijing National Laboratory for Molecular | Wang M.-X.,Tsinghua University
Journal of the American Chemical Society | Year: 2013

Anion-π interactions have been systematically studied using tetraoxacalix[2]arene[2]triazine 1, an electron-deficient and cavity self-tunable macrocyclic host, as an electron-neutral molecular probe. As revealed by electrospray ionization mass spectrometry (ESI-MS), fluorescence titration and X-ray crystallography, tetraoxacalix[2]arene[2]triazine has been found to form 1:1 complexes with four typical polyatomic anions of different geometries and shapes in the gaseous phase, in solution, and in the solid state. The association constants for the formation of anion-π complexes in acetonitrile are in the range of 239 to 16950 M-1, following the order of 1·NO3 - > 1·BF4 - > 1·PF6 - > 1·SCN -. X-ray molecular structures of the complexes showed that two opposing triazine rings of tetraoxacalix[2]arene[2]triazine act as a pair of tweezers to interact with the included anions through cooperative anion-π and lone-pair electron-π interactions. The generality of anion-π interactions and diverse anion-π interaction motifs can provide a new dimension in the study of molecular recognition and self-assembly. Moreover, this study potentiates the effect of anion-π interactions in chemical and biological systems, especially those involving anion and electron-deficient aromatic species. © 2012 American Chemical Society.


Liu Z.,Peking University | Liu Z.,CAS Beijing National Laboratory for Molecular | Huang Y.,Peking University | Huang Y.,St Jude Childrens Research Hospital
Protein Science | Year: 2014

The past decade has witnessed great advances in our understanding of protein structure-function relationships in terms of the ubiquitous existence of intrinsically disordered proteins (IDPs) and intrinsically disordered regions (IDRs). The structural disorder of IDPs/IDRs enables them to play essential functions that are complementary to those of ordered proteins. In addition, IDPs/IDRs are persistent in evolution. Therefore, they are expected to possess some advantages over ordered proteins. In this review, we summarize and survey nine possible advantages of IDPs/IDRs: economizing genome/protein resources, overcoming steric restrictions in binding, achieving high specificity with low affinity, increasing binding rate, facilitating posttranslational modifications, enabling flexible linkers, preventing aggregation, providing resistance to non-native conditions, and allowing compatibility with more available sequences. Some potential advantages of IDPs/IDRs are not well understood and require both experimental and theoretical approaches to decipher. The connection with protein design is also briefly discussed. © 2014 The Protein Society.


Duan H.,Tsinghua University | Wang D.,Tsinghua University | Kou Y.,CAS Beijing National Laboratory for Molecular | Li Y.,Tsinghua University
Chemical Communications | Year: 2013

Rhodium-nickel bimetallic nanocrystals were fabricated with high activity in hydrogenation of olefins, nitroarenes and arenes at room temperature, indicating that bimetallic nanocrystals of noble and non-noble metals represent a novel kind of nanocatalyst. This journal is © 2013 The Royal Society of Chemistry.


Ouyang K.,CAS Beijing National Laboratory for Molecular | Ouyang K.,Peking University | Liang Y.,Hunan Normal University | Xi Z.,Peking University
Organic Letters | Year: 2012

A variety of silacycles including benzosiloles, six- and eight-membered silacyclic skeletons, were efficiently synthesized via a Pd-catalyzed intramolecular Mizoroki-Heck reaction of vinylsilanes. © 2012 American Chemical Society.


Zhang W.,CAS Suzhou Institute of Nano Technology and Nano Bionics | Shi Z.,CAS Suzhou Institute of Nano Technology and Nano Bionics | Zhang F.,CAS Suzhou Institute of Nano Technology and Nano Bionics | Liu X.,CAS Suzhou Institute of Nano Technology and Nano Bionics | And 2 more authors.
Advanced Materials | Year: 2013

A superhydrophobic-superoleophilic PVDF membrane is fabricated via an inert solvent-induced phase inversion for effective separation of both micrometer and nanometer-sized surfactant-free and surfactant-stabilized water-in-oil emulsions solely driven by gravity, with high separation efficiency (oil purity in filtrate after separation > 99.95 wt%) and high flux, which is several times higher than those of commercial filtration membranes and reported materials with similar permeation properties. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Shi Z.,CAS Suzhou Institute of Nano Technology and Nano Bionics | Zhang W.,CAS Suzhou Institute of Nano Technology and Nano Bionics | Zhang F.,CAS Suzhou Institute of Nano Technology and Nano Bionics | Liu X.,CAS Suzhou Institute of Nano Technology and Nano Bionics | And 3 more authors.
Advanced Materials | Year: 2013

As an alternative to polymer membranes, ultrathin free-standing single-walled carbon-nanotube network films are used to realize oil/water separation with ultrahigh flux. The films with tunable thickness of the tens of nanometer scale can effectively separate both micrometer and nanometer-sized surfactant-free and surfactant-stabilized water-in-oil emulsions with a flux 2-3 orders of magnitude higher than commercial filtration membranes with similar separation performance. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Qian C.,Second Military Medical University | Cao X.,Second Military Medical University | Cao X.,CAS Beijing National Laboratory for Molecular
Annals of the New York Academy of Sciences | Year: 2013

Toll-like receptors (TLRs) are critical pattern recognition receptors (PRRs) that recognize pathogen-associated molecular patterns (PAMPs), which are conserved and specific molecular "signatures" expressed by pathogens. TLR ligation triggers distinct but shared signaling pathways that lead to effector mechanisms in innate immune responses. TLR specificity and activation are strictly and finely tuned at multiple levels of various signal transduction pathways, resulting in complex signaling platforms. Many molecules, ranging from membrane and cytosol to nuclear, contribute to TLR ligand discrimination or receptor signaling and play different roles in the regulation of TLR responses via different mechanisms, such as cross-regulation, protein modification, helper cofactors, and posttranscriptional and epigenetic regulation. Herein, we summarize the most recent literature that provides new insight into regulation of TLR signaling-triggered innate immune responses. A greater understanding of the mechanisms underlying the control of TLR signaling may provide new targets for therapeutic intervention for infections and inflammatory diseases. © 2012 The New York Academy of Sciences.


Jiang L.,CAS Institute of Physics | Yang T.,CAS Institute of Physics | Liu F.,Sun Yat Sen University | Dong J.,Tsinghua University | And 6 more authors.
Advanced Materials | Year: 2013

Large-scale, uniform, vertically standing graphene with atomically thin edges are controllably synthesized on copper foil using a microwave-plasma chemical vapor deposition system. A growth mechanism for this system is proposed. This film shows excellent field-emission properties, with low turn-on field of 1.3 V μm-1, low threshold field of 3.0 V μm -1 and a large field-enhancement factor more than 10 000. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zhang X.,Tsinghua University | Wang S.,Tsinghua University | Liu M.,CAS Beijing National Laboratory for Molecular | Tao L.,Tsinghua University | Wei Y.,Tsinghua University
Nanoscale | Year: 2013

Water soluble and biocompatible fluorescent organic nanoparticles based on aggregation-induced emission (AIE) material were facilely prepared by mixing AIE material and surfactant. The utilization of such fluorescent organic nanoparticles for cell imaging applications was further explored. © 2013 The Royal Society of Chemistry.


Zhang C.,CAS Beijing National Laboratory for Molecular | Lai L.,Peking University
Biochemical Society Transactions | Year: 2011

Structure-based drug design for chemical molecules has been widely used in drug discovery in the last 30 years. Many successful applications have been reported, especially in the field of virtual screening based on molecular docking. Recently, there has been much progress in fragment-based as well as de novo drug discovery. As many protein-protein interactions can be used as key targets for drug design, one of the solutions is to design protein drugs based directly on the protein complexes or the target structure. Compared with protein-ligand interactions, protein-protein interactions are more complicated and present more challenges for design. Over the last decade, both sampling efficiency and scoring accuracy of protein-protein docking have increased significantly. We have developed several strategies for structurebased protein drug design. A grafting strategy for key interaction residues has been developed and successfully applied in designing erythropoietin receptor-binding proteins. Similarly to small-molecule design, we also tested de novo protein-binder design and a virtual screen of protein binders using protein-protein docking calculations. In comparison with the development of structure-based small-molecule drug design, we believe that structure-based protein drug design has come of age. ©The Authors Journal compilation ©2011 Biochemical Society.


Xue B.,Beihang University | Gao L.,Beihang University | Hou Y.,Beihang University | Liu Z.,Agilent Technologies | And 2 more authors.
Advanced Materials | Year: 2013

A temperature controlled dual water/oil on-off switch is achieved by using a PMMA-b-PNIPAAm block-copolymer coated mesh, determined by the conformational change of the PNIPAAm chain around the lower critical solution temperature (LCST) and also the cooperation between PNIPAAm and PMMA. Water can permeate through the BCP-coated mesh, and oil cannot below the LCST, whereas oil can and water cannot above the LCST. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zhang X.,Tsinghua University | Wang S.,Tsinghua University | Liu M.,CAS Beijing National Laboratory for Molecular | Zhang Y.,Tsinghua University | And 2 more authors.
ACS Applied Materials and Interfaces | Year: 2013

Aggregation-induced emission (AIE) materials were facilely incorporated into mesoporous silica nanoparticles (MSNs) via one-pot surfactant templated method. Cell imaging and cancer therapy applications of such fluorescent MSNs were further explored. We demonstrated that AIE-MSN nanocomposites showed strong fluorescence and uniform morphology, making them promising for both cell imaging and cancer therapy. © 2013 American Chemical Society.


Gan L.,CAS Beijing National Laboratory for Molecular | Gan L.,CAS Shanghai Institute of Organic Chemistry
Chemical Record | Year: 2015

Replacement of a pentagon in [60]fullerene with five oxygen atoms yields the open-cage compound C55O5 with five carbonyl groups on the rim of the orifice. Our attempts to synthesize such a target molecule starting from C60 have led us to prepare the fullerene-mixed peroxides such as C60(OO-t-Bu)6 with all the peroxo addends surrounding the same pentagon. Further investigations of the peroxide chemistry have generated various open-cage fullerene derivatives, including the carbon monoxide encapsulated endohedral compound CO@C59O6. This Personal Account mainly discusses peroxide-based processes resulting in selective cleavage of the fullerene skeleton bonds. © 2014 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA Weinheim.


Liu W.,CAS Beijing National Laboratory for Molecular
International Journal of Quantum Chemistry | Year: 2014

Under the no-photon approximation, an effective quantum electrodynamics (QED) Hamiltonian can be constructed based solely on charge conjugation symmetry. It serves as the basis not only for the emerging field of "molecular QED" but also for various approximate Hamiltonians, including the standard no-pair ones. The whole spectrum of relativistic Hamiltonians is hence completed. © 2013 Wiley Periodicals, Inc.


Zhang B.,Beijing University of Chemical Technology | Wang J.,CAS Beijing National Laboratory for Molecular | Zhang X.,Beijing University of Chemical Technology
Langmuir | Year: 2013

We used the lattice Boltzmann method to investigate how the hierarchical structure of a rough solid surface, which in this work is modeled as the microstructure (micropillars) covered with nanostructures (nanopillars), affects the contact angle of microdroplets atop of the solid surface and the wetting transition between the Wenzel and Cassie states. Our simulation results show that the Wenzel-to-Cassie state transition can be achieved by decreasing the fluid-solid attraction, increasing the micropillar spacing, or coating the microstructures with nanostructures. For the effect of the hierarchical structure on the contact angle, we find that the micropillars show a negligible effect on the contact angle, but they may affect the sliding angle. In contrast, it is the nanostructure that determines the contact angle. The contact angle increases with the nanopillar length until reaching a maximal value, but its dependence on the nanopillar spacing becomes more complicated. The contact angle may first increase with the nanopillar spacing and then decreases, or decreases monotonously, depending on whether the liquid enters the nanostructure or not. In this work, we also demonstrate in the presence of contact line pinning, that the pinning effect affects the apparent contact angle. © 2013 American Chemical Society.


Jiang H.,CAS Beijing National Laboratory for Molecular
Journal of Chemical Physics | Year: 2013

The semi-local Becke-Johnson (BJ) exchange-correlation potential and its modified form proposed by Tran and Blaha (TB-mBJ) have attracted a lot of interest recently because of the surprisingly accurate band gaps they can deliver for many semiconductors and insulators. In this work, we have investigated the performance of the TB-mBJ potential for the description of electronic band structures in a comprehensive set of semiconductors and insulators. We point out that a perturbative use of the TB-mBJ potential can give overall better results. By investigating a set of IIB-VI and III-V semiconductors, we point out that although the TB-mBJ approach can describe the band gap of these materials quite well, the binding energies of semi-core d-states in these materials deviate strongly from experiment. The difficulty of the TB-mBJ potential to describe the localized states is likely the cause for the fact that the electronic band structures of Cu2O and La 2O3 are still poorly described. Based on these observations, we propose to combine the TB-mBJ approach with the Hubbard U correction for localized df states, which is able to provide overall good descriptions for both the band gaps and semi-core states binding energies. We further apply the approach to calculate the band gaps of a set of Ti(IV)-oxides, many of which have complicated structures so that the more advanced methods like GW are expensive to treat directly. An overall good agreement with experiment is obtained, which is remarkable considering its little computational efforts compared to GW. © 2013 American Institute of Physics.


Liu W.,CAS Beijing National Laboratory for Molecular | Lindgren I.,Gothenburg University
Journal of Chemical Physics | Year: 2013

The current field of relativistic quantum chemistry (RQC) has been built upon the no-pair and no-retardation approximations. While retardation effects must be treated in a time-dependent manner through quantum electrodynamics (QED) and are hence outside RQC, the no-pair approximation (NPA) has to be removed from RQC for it has some fundamental defects. Both configuration space and Fock space formulations have been proposed in the literature to do this. However, the former is simply wrong, whereas the latter is still incomplete. To resolve the old problems pertinent to the NPA itself and new problems beyond the NPA, we propose here an effective many-body (EMB) QED approach that is in full accordance with standard methodologies of electronic structure. As a first application, the full second order energy E2 of a closed-shell many-electron system subject to the instantaneous Coulomb-Breit interaction is derived, both algebraically and diagrammatically. It is shown that the same E2 can be obtained by means of 3 Goldstone-like diagrams through the standard many-body perturbation theory or 28 Feynman diagrams through the S-matrix technique. The NPA arises naturally by retaining only the terms involving the positive energy states. The potential dependence of the NPA can be removed by adding in the QED one-body counter terms involving the negative energy states, thereby leading to a "potential-independent no-pair approximation" (PI-NPA). The NPA, PI-NPA, EMB-QED, and full QED then span a continuous spectrum of relativistic molecular quantum mechanics. © 2013 AIP Publishing LLC.


Tian D.,Beihang University | Zhai J.,Beihang University | Song Y.,CAS Beijing National Laboratory for Molecular | Jiang L.,Beihang University
Advanced Functional Materials | Year: 2011

Surface wettability as a response to the cooperation of different stimuli has been intensively studied and provides more advantages than as a response to a single stimulus. Recently, we demonstrated the patterned wettability transition from the Cassie to the Wenzel state on a superhydrophobic aligned-ZnO-nanorod array surface via a photoelectric cooperative wetting process. However, the specific aligned-nanorod array structure of such devices is easily damaged due to their low mechanical strength and cannot sustain multiple transfer printing. Meanwhile, the patterned wetting process is not easily controlled due to the air-permeable structure of adjacent nanorods. As a result, in practice, it is difficult to apply liquid reprography on such a nanostructure. Here, we demonstrate photoelectric cooperative induced patterned wetting on the superhydrophobic aligned-nanopore array surface of TiO 2-coated nanoporous AAO film, which has a high mechanical strength and excellent controllability. Liquid reprography is achieved through the patterned wetting process on the superhydrophobic aligned-nanopore array surface, which is a new progression in liquid reprography, and is promising for gearing up the application of photoelectric cooperative liquid reprography. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Suo T.,CAS Beijing National Laboratory for Molecular | Yan D.,Beijing Normal University
Polymer | Year: 2011

A theoretical study on the phase behaviors of a polymer solution confined between two coaxial cylindrical walls is presented. For the case of a neutral inner cylinder, the spinodal point derived by the Gaussian fluctuation theory is confinement-independent because of the existence of a free dimension in the system. The kinetic analysis indicates that the fluctuation modes always have a component of a plane wave along the axial direction, which can lead to the formation of a periodic-like concentration pattern. On the other hand, the equilibrium structure of the system is obtained by the self-consistent mean-field theory (SCMFT) and the interplay between the "wetting" phenomenon and the phase separation is observed by modifying the property of the inner cylindrical wall. In particular, our results can be regarded as a hint to interpret the mechanism of the formation of the shish-kebab structure observed in the field of polymer crystallization. © 2011 Elsevier Ltd.


Zhang Z.,Huazhong University of Science and Technology | Xiao F.,Huazhong University of Science and Technology | Qian L.,Huazhong University of Science and Technology | Xiao J.,Huazhong University of Science and Technology | And 2 more authors.
Advanced Energy Materials | Year: 2014

The integration of graphene nanosheets on the macroscopic level using a self-assembly method has been recognized as one of the most effective strategies to realize the practical applications of graphene materials. Here, a facile and scalable method is developed to synthesis two types of graphene-based networks, manganese dioxide (MnO2)-graphene foam and carbon nanotube (CNT)-graphene foam, by solution casting and subsequent electrochemical methods. Their practical applications in flexible all-solid-state asymmetric supercapacitors are explored. The proposed method facilitates the structural integration of graphene foam and the electroactive material and offers several advantages including simplicity, efficiency, low-temperature, and low-cost. The as-prepared MnO2-graphene and CNT-graphene electrodes exhibit high specific capacitances and rate capability. By using polymer gel electrolytes, a flexible all-solid-state asymmetric supercapacitor was synthesized with MnO 2-graphene foam as the positive electrode and CNT-graphene as the negative electrode. The asymmetric supercapacitors can be cycled reversibly in a high-voltage region of 0 to 1.8 V and exhibit high energy density, remarkable rate capability, reasonable cycling performance, and excellent flexibility. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Based on the consideration that compound 1 with a -PO3H2 group can be hydrolyzed into compound 3 which shows low solubility in aqueous solutions and thus aggregation can occur easily, a new fluorescence turn-on assay has been constructed for alkaline phosphatase (ALP) with compound 1. ALP at concentrations as low as 18 mU mL(-1) can be assayed with compound 1. Moreover, compound 1 has been successfully applied for ALP assay in living cells. Also, compound 1 is useful for screening inhibitors of ALP.


Yan X.,Max Planck Institute of Colloids and Interfaces | Li J.,CAS Beijing National Laboratory for Molecular | Mohwald H.,Max Planck Institute of Colloids and Interfaces
Advanced Materials | Year: 2012

3D hybrid colloidal spheres with integrated functions and collective properties are fabricated using a variety of common inorganic nano-objects as building blocks in association with polyelectrolyte encapsulation through a facile template strategy. The fabrication strategy is generally suited for design of functional colloidal spheres in a simple and controllable manner, and thus opens a new avenue for developing hybrid materials with multiple functions and collective properties. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Liu K.,Beihang University | Du J.,Beihang University | Wu J.,Beihang University | Jiang L.,Beihang University | Jiang L.,CAS Beijing National Laboratory for Molecular
Nanoscale | Year: 2012

Functional integration is an inherent characteristic for multiscale structures of biological materials. In this contribution, we first investigate the liquid-solid adhesive forces between water droplets and superhydrophobic gecko feet using a high-sensitivity micro-electromechanical balance system. It was found, in addition to the well-known solid-solid adhesion, the gecko foot, with a multiscale structure, possesses both superhydrophobic functionality and a high adhesive force towards water. The origin of the high adhesive forces of gecko feet to water could be attributed to the high density nanopillars that contact the water. Inspired by this, polyimide films with gecko-like multiscale structures were constructed by using anodic aluminum oxide templates, exhibiting superhydrophobicity and a strong adhesive force towards water. The static water contact angle is larger than 150° and the adhesive force to water is about 66 μN. The resultant gecko-inspired polyimide film can be used as a "mechanical hand" to snatch micro-liter liquids. We expect this work will provide the inspiration to reveal the mechanism of the high-adhesive superhydrophobic of geckos and extend the practical applications of polyimide materials. © 2012 The Royal Society of Chemistry.


Ni J.,Suzhou University | Li Y.,CAS Beijing National Laboratory for Molecular
Advanced Energy Materials | Year: 2016

Carbon nanomaterials including fullerenes, carbon nanotubes, graphene, and their assemblies represent a unique type of materials in diverse formats and dimensions. They feature a large surface area, superior conductivity, fast charge transport, and intrinsic stability, which are essentially required for vari-ous electrochemical energy storage (EES) systems such as Li-ion batteries, supercapacitors, and redox flow cells. The scaled-up and reliable production and assembly of carbon nanomaterials is a prerequisite for the development of carbon nanomaterial-based EES devices. In this progress report, the preparation of carbon nanostructures and the state-of-the-art applications of carbon nanomaterials with different dimensions in versatile EES systems are summarized. The importance of the synergetic effect induced by interactions between nanocarbons and active electrode species is highlighted. The main challenges and prospects in this field are also discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


A density functional theory study reveals that the dehydrogenation of ethanol catalyzed by an aliphatic PNP pincer ruthenium complex, (PNP)Ru(H)CO {1Ru, PNP = bis[2-(diisopropylphosphino)ethyl]amino}, proceeds via a self-promoted mechanism that features an ethanol molecule acting as a bridge to assist the transfer of a proton from ligand nitrogen to the metal center for the formation of H2. The very different catalytic properties between the aromatic and aliphatic pincer ligand in ruthenium complexes are analyzed. The potential of an iron analogue of 1Ru, (PNP)Fe(H)CO (1Fe), as a catalyst for the dehydrogenation of ethanol was evaluated computationally. The calculated total free energy barrier of ethanol dehydrogenation catalyzed by 1Fe is only 22.1 kcal/mol, which is even 0.7 kcal/mol lower than the calculated total free energy barrier of the reaction catalyzed by 1 Ru. Therefore, the potential of 1Fe as a low-cost and high-efficiency catalyst for the production of hydrogen from ethanol is promising. © 2013 American Chemical Society.


Yao L.,CAS Beijing National Laboratory for Molecular | Xu S.,University of Houston
Nanotechnology Reviews | Year: 2014

Advances in bionanotechnology promise to allow medical diagnosis and therapy through the channel of molecular imaging. Combining biological science and modern detection techniques, molecular imaging has the ability to penetrate biomedical processes at the molecular and cellular level. Magnetic nanoparticles (MNP), broadly defined as particles of tens of nm to approximately 2 μm in diameter in this review, are playing an increasingly important role in molecular imaging. They act as contrast agents to remarkably enhance the signal. The precise determination of the position and quantity of MNP is critical for these applications. This review describes the advances in the development of detection techniques for magnetic particles used in molecular imaging and diagnosis. The techniques are categorized as high magnetic field techniques and low magnetic field techniques. The high-field studies focus on magnetic resonance imaging (MRI). The ultra-low-field (ULF) studies include several of the most recent techniques: giant magnetoresistance sensors, superconducting quantum interference devices, atomic magnetometers, and magnetic particle imaging. The advantages and disadvantages of each method are discussed.


Yan X.,Max Planck Institute of Colloids and Interfaces | Blacklock J.,Max Planck Institute of Colloids and Interfaces | Li J.,CAS Beijing National Laboratory for Molecular | Mohwald H.,Max Planck Institute of Colloids and Interfaces
ACS Nano | Year: 2012

Figure Persented: We present a general strategy to create polypeptide-gold nanoconjugates by a one-pot synthesis approach, where polypeptides act not only as capping agents but also as reductants for the formation of gold nanoparticles without the need of an additional reducing agent. The present approach is environmentally benign, facile, and flexible for the design of functional polypeptide-gold nanoconjugates. As a demonstration of as-synthesized nanoconjugates for biomedical applications, the resulting positively charged polypeptide-conjugated gold nanoparticles are applied for gene delivery. A gradual and prolonged intracellular uptake and transfection is achieved, and transfection activity is maintained for almost two weeks with no obvious cytotoxicity. The biologically based method presented in this work will provide a new alternative in creating a variety of multifunctional polypeptide-metallic nanoconjugates in a simple and straightforward manner, which will be more advantageous for their applications in biomedicine. © 2011 American Chemical Society.


Zhan C.,CAS Beijing National Laboratory for Molecular | Li A.D.Q.,Washington State University
Current Organic Chemistry | Year: 2011

Perylene diimides (PDIs) have been playing important roles in several active fields. Therefore, we will first review the current methods to modify the skeleton of perylene diimides. Next, PDI self-assemblies and PDI folded nanostructures and chemically restrained PDI nanostructures are presented. Unusual physical properties due to nanostructures formation are discussed including the absorption band intensity reversal and π-stack red-fluorescence emission. Because of interesting π-stacked structures, PDI derivatives are considered as potential candidates for photovoltaic applications and organic electronics. More importantly, π-stacking can be tuned when the dihedral angle of the two naphthalene planes varies, thus resulting in adjusted interacting forces. Such cooperative forces lead to the discovery of molecular code phenomena, which will have profound impact an future bi-molecular reaction designs. © 2011 Bentham Science Publishers Ltd.


Liu K.,Beihang University | Jiang L.,Beihang University | Jiang L.,CAS Beijing National Laboratory for Molecular
Nanoscale | Year: 2011

Metals are important and irreplaceable engineered materials in our society. Nature is a school for scientists and engineers, which has long served as a source of inspiration for humans. Inspired by nature, a variety of metallic surfaces with special wettability have been fabricated in recent years through the combination of surface micro- and nanostructures and chemical composition. These metallic surfaces with special wettability exhibit important applications in anti-corrosion, microfluidic systems, oil-water separation, liquid transportation, and other fields. Recent achievements in the fabrication and application of metallic surfaces with special wettability are presented in this review. The research prospects and directions of this field are also briefly addressed. We hope this review will be beneficial to expand the practical applications of metals and offer some inspirations to the researchers in the fields of engineering, biomedicine, and materials science. © 2011 The Royal Society of Chemistry.


Wang H.,Shanghai University | Yang S.-T.,Shanghai University | Yang S.-T.,Southwest University for Nationalities | Cao A.,Shanghai University | And 2 more authors.
Accounts of Chemical Research | Year: 2013

A diverse array of carbon nanomaterials (NMs), including fullerene, carbon nanotubes (CNTs), graphene, nanodiamonds, and carbon nanoparticles, have been discovered and widely applied in a variety of industries. Carbon NMs have been detected in the environment and have a strong possibility of entering the human body. The safety of carbon NMs has thus become a serious concern in academia and society. To achieve strict biosafety assessments, researchers need to fully understand the effects and fates of NMs in the human body, including information about absorption, distribution, metabolism, excretion, and toxicity (ADME/T).To acquire the ADME data, researchers must quantify NMs, but carbon NMs are very difficult to quantify in vivo. The carbon background in a typical biological system is high, particularly compared with the much lower concentration of carbon NMs. Moreover, carbon NMs lack a specific detection signal. Therefore, isotopic labeling, with its high sensitivity and specificity, is the first choice to quantify carbon NMs in vivo. Previously, researchers have used many isotopes, including 13C, 14C, 125I, 131I, 3H, 64Cu, 111In, 86Y, 99mTc, and 67Ga, to label carbon NMs. We used these isotopic labeling methods to study the ADME of carbon NMs via different exposure pathways in animal models.Except for the metabolism of carbon NMs, which has seldom been investigated, significant amounts of data have been reported on the in vivo absorption, distribution, excretion, and toxicity of carbon NMs, which have revealed characteristic behaviors of carbon NMs, such as reticuloendothelial system (RES) capture. However, the complexity of the biological systems and diverse preparation and functionalization of the same carbon NMs have led to inconsistent results across different studies. Therefore, the data obtained so far have not provided a compatible and systematic profile of biosafety. Further efforts are needed to address these problems.In this Account, we review the in vivo quantification methods of carbon NMs, focusing on isotopic labeling and tracing methods, and summarize the related labeling, purification, bio-sampling, and detection of carbon NMs. We also address the advantages, applicable situations, and limits of various labeling and tracing methods and propose guidelines for choosing suitable labeling methods. A collective analysis of the ADME information on various carbon NMs in vivo would provide general principles for understanding the fate of carbon NMs and the effects of chemical functionalization and aggregation of carbon NMs on their ADME/T in vivo and their implications in nanotoxicology and biosafety evaluations. © 2012 American Chemical Society.


Liu J.,CAS Beijing National Laboratory for Molecular
Journal of Chemical Physics | Year: 2014

We show a new imaginary time path integral based method - path integral Liouville dynamics (PILD), which can be derived from the equilibrium Liouville dynamics [J. Liu and W. H. Miller, J. Chem. Phys. 134, 104101 (2011)] in the Wigner phase space. Numerical tests of PILD with the simple (white noise) Langevin thermostat have been made for two strongly anharmonic model problems. Since implementation of PILD does not request any specific form of the potential energy surface, the results suggest that PILD offers a potentially useful approach for general condensed phase molecular systems to have the two important properties: conserves the quantum canonical distribution and recovers exact thermal correlation functions (of even nonlinear operators, i.e., nonlinear functions of position or momentum operators) in the classical, high temperature, and harmonic limits. © 2014 AIP Publishing LLC.


Li Y.,CAS Technical Institute of Physics and Chemistry | Yu T.,CAS Technical Institute of Physics and Chemistry | Zeng Y.,CAS Technical Institute of Physics and Chemistry | Chen J.,CAS Technical Institute of Physics and Chemistry | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2013

A three-component homogeneous catalyst system has been prepared with an IrIII complex as the photosensitizer, artificial hydrogenases bearing a diiron core and dendritic frameworks as the proton reduction catalyst, and triethylamine as the sacrificial electron donor. An initial turnover frequency of over 7240h-1 and a quantum yield of up to 28 % were determined for the photocatalytic evolution of hydrogen. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Jiang L.,University Utrecht | De Folter J.W.J.,University Utrecht | Huang J.,CAS Beijing National Laboratory for Molecular | Philipse A.P.,University Utrecht | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2013

The co-assembly of spherical colloids and surfactant-cyclodextrin microtubes yields a library of dynamic colloid-in-tube structures, including helices. In situ observations of these structures, including their thermo-reversible assembly and disassembly, demonstrate the potential of the interplay between molecular and colloidal self-assembly, thereby providing a novel route to temperature-sensitive particle alignment and release. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Pei J.,Peking University | Yin N.,Peking University | Ma X.,Peking University | Lai L.,Peking University | And 2 more authors.
Journal of the American Chemical Society | Year: 2014

In this Perspective, we focus on new, systems-centric views of structure-based drug design (SBDD) that we believe will impact future drug discovery research and development. We will first discuss new ways to identify drug targets based on systems intervention analysis, and then we will introduce emerging SBDD methods driven by advancements in systems biology. © 2014 American Chemical Society.


He M.,Sinopec | He M.,East China Normal University | Sun Y.,CAS Shanghai Advanced Research Institute | Sun Y.,Shanxi Institute of Coal CAS Chemistry | Han B.,CAS Beijing National Laboratory for Molecular
Angewandte Chemie - International Edition | Year: 2013

How green was my valley: Green carbon science focuses on the transformations of carbon-containing compounds in the entire carbon cycle. The ultimate aim is to use carbon resources efficiently and minimize the net CO 2 emission. This holistic view also has ramifications for related fields including petroleum refining and the production of liquid fuels and chemicals from coal, methane, CO2, and biomass. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Xiao T.,Sun Yat Sen University | Dong X.,Sun Yat Sen University | Zhou L.,Sun Yat Sen University | Zhou L.,CAS Beijing National Laboratory for Molecular
Organic and Biomolecular Chemistry | Year: 2013

A general and practical method to synthesize 2-substituted benzofurans and indoles is described. This method employs easily accessible N-tosylhydrazones and o-hydroxy or o-amino phenylacetylenes as substrates. The reaction proceeds through a CuBr-catalyzed coupling-allenylation-cyclization sequence under ligand-free conditions. This journal is © 2013 The Royal Society of Chemistry.


Duan R.,Huazhong University of Science and Technology | Xia F.,Huazhong University of Science and Technology | Jiang L.,CAS Beijing National Laboratory for Molecular
ACS Nano | Year: 2013

Inspired by biological cell membranes, various "smart" and efficient gating nanoporous devices have been proposed to imitate and to understand life processes. Nanodevices under development with enhanced gating efficiency could play pivotal roles in biosensing and drug delivery. In this Perspective, we highlight an important development by Willner and colleagues that is detailed in this issue of ACS Nano. They designed a new "smart" nanodevice with both "sense" and "release" functionalities for drug delivery based on a nanoporous material, mesoporous silica nanoparticles. We outline recent progress in designing intelligently gated nanoporous devices in material science and nanotechnology. We also summarize new strategies designed for drug delivery based on mesoporous materials. With continuing efforts, we expect more powerful nanodevices to be developed and used in clinical and other real-word applications. © 2013 American Chemical Society.


Kong H.,Tsinghua University | Liu D.,Tsinghua University | Liu D.,CAS Beijing National Laboratory for Molecular | Zhang S.,Tsinghua University | Zhang X.,Tsinghua University
Analytical Chemistry | Year: 2011

Cross-reactive sensor arrays, known as "chemical noses", offer an alternative to time-consuming analytical methods. Here, we report a sensor array based on nanomaterial-assisted chemiluminescence (CL) for protein sensing and cell discrimination. We have found that the CL efficiencies are improved to varied degrees for a given protein or cell line on catalytic nanomaterials. Distinct CL response patterns as "fingerprints" can be obtained on the array and then identified through linear discriminant analysis (LDA). The sensing of 12 kinds of proteins at three concentrations, as well as 12 types of human cell lines among normal, cancerous, and metastatic, has been performed. Compared with most fluorescent or colorimetric approaches which rely on the strong interaction between analytes and sensing elements, our array offers the advantage of both sensitivity and reversibility. © 2011 American Chemical Society.


Wang Q.,CAS Hefei Key Laboratory of Novel Thin Film Solar Cells | Wang X.,CAS Hefei Key Laboratory of Novel Thin Film Solar Cells | Wang X.,Soochow University of China | Chai Z.,Soochow University of China | Hu W.,CAS Beijing National Laboratory for Molecular
Chemical Society Reviews | Year: 2013

Carbon nanotubes (CNTs) and graphene, and materials based on these, are largely used in multidisciplinary fields. Many techniques have been put forward to synthesize them. Among all kinds of approaches, the low-temperature plasma approach is widely used due to its numerous advantages, such as highly distributed active species, reduced energy requirements, enhanced catalyst activation, shortened operation time and decreased environmental pollution. This tutorial review focuses on the recent development of plasma synthesis of CNTs and graphene based materials and their electrochemical application in fuel cells. This journal is © The Royal Society of Chemistry.


Wang Y.,CAS Beijing National Laboratory for Molecular | Zhan X.,Peking University
Advanced Energy Materials | Year: 2016

Layer-by-layer (LL) processes, i.e., sequential deposition of different active layers, are widely used in the fabrication of organic solar cells (OSCs). Recently, LL vacuum deposition and LL solution processes have attracted considerable attention. LL processing presents some advantages over the blend method: a) donor and acceptor layers can be easily and independently controlled and optimized; b) the charge carriers dissociated from excitons at the donor-acceptor interface are confined to each phase, so bimolecular recombination losses can be reduced; c) bilayer geometries enable an easier way for understanding the physical processes taking place at the donor-acceptor interface; d) desired vertical phase separation for charge extraction can be obtained through changing the sequence of donor and acceptor deposition. This report summarizes the recent developments of LL processed OSCs. The remaining problems and challenges, and the key research direction in near future are discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Lang X.,Nanyang Technological University | Leow W.R.,Nanyang Technological University | Zhao J.,CAS Beijing National Laboratory for Molecular | Chen X.,Nanyang Technological University
Chemical Science | Year: 2015

Selective photocatalytic aerobic oxidation, which can be conducted under ambient conditions, is of great importance towards achieving sustainable chemistry. However, its practical applications are undermined by several challenges, such as low selectivity, sluggish reaction rates, and the requirement of UV light irradiation. Herein, we report a new concept of synergistic photocatalytic oxidation, for which two seemingly irrelevant reactions can be achieved in one photocatalytic system through the synergistic interplay of reactants and catalyst. As proof of concept, two challenging reactions, the aerobic oxidation of sulfide and the aerobic oxidative formylation of amine with methanol, were employed to demonstrate such synergistic photocatalytic aerobic oxidation under visible-light irradiation. This work could pave the way for highly selective photoredox catalysis via rational design based on mechanistic insight. © The Royal Society of Chemistry 2015.


Cui N.,Lanzhou University | Wu W.,Lanzhou University | Zhao Y.,CAS Beijing National Laboratory for Molecular | Bai S.,Lanzhou University | And 3 more authors.
Nano Letters | Year: 2012

Nanogenerator has been a very important energy harvesting technology through directly deforming piezoelectric material. Here, we report a new magnetic force driven contactless nanogenerator (CLNG), which avoids the direct contact between nanogenerator and mechanical movement source. The CLNG can harvest the mechanical movement energy in a noncontact mode to generate electricity. Their output voltage and current can be as large as 3.2 V and 50 nA, respectively, which is large enough to power up a liquid crystal display. We also demonstrate a means by which a magnetic sensor can be built. © 2012 American Chemical Society.


Wang Q.,Beihang University | Yao X.,City University of Hong Kong | Liu H.,Beihang University | Quere D.,French National Center for Scientific Research | And 2 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

The ability to control drops and their movements on phobic surfaces is important in printing or patterning, microfluidic devices, and water-repellent materials. These materials are always micro-/nanotextured, and a natural limitation of repellency occurs when drops are small enough (as in a dew) to get trapped in the texture. This leads to sticky Wenzel states and destroys the superhydrophobicity of the material. Here, we show that droplets of volume ranging from femtoliter (fL) to microliter (μL) can be self-removed from the legs of water striders. These legs consist of arrays of inclined tapered setae decorated by quasi-helical nanogrooves. The different characteristics of this unique texture are successively exploited as water condenses, starting from self-penetration and sweeping effect along individual cones, to elastic expulsion between flexible setae, followed by removal at the anisotropic leg surface. We envision that this antifogging effect at a very small scale could inspire the design of novel applicable robust water-repellent materials for many practical applications.


Xu F.,CAS Beijing National Laboratory for Molecular | Yan D.,Beijing Normal University
Applied Physics Letters | Year: 2011

In this letter, we employ a three-dimensional master equation calculation to investigate the mobility dependence of bulk heterojunction (BHJ) solar cell performance. By taking energetic disorder and morphology into consideration, we show mobility-enhanced device efficiency with a remarkable charge transport loss induced by molecular disorder and an open circuit voltage loss in high mobility region due to morphological defect-assisted bimolecular recombination. The result suggests that the description of interfacial processes is crucial in the modeling of BHJ photovoltaic devices. © 2011 American Institute of Physics.


Liu H.,East China University of Science and Technology | Li C.,East China University of Science and Technology | Qiu D.,CAS Beijing National Laboratory for Molecular | Tong X.,East China University of Science and Technology
Journal of the American Chemical Society | Year: 2011

A palladium-catalyzed iodine atom transfer cycloisomerization of (Z)-1-iodo-1,6-diene has been developed, which provides a facile method to construct six-memebered heterocycles bearing an alkyl iodide group. The ligand screening shows that both the type and the quantity of ligand impose significant influences on this transformation, and the combination of 30 mol % 1,1′-bis(diphenylphosphino)ferrocene (DPPF) and 10 mol % Pd(OAc) 2 is the optimal choice. The catalytic cycle, consisting of oxidative addition of Pd(0) to vinyl iodide, intramolecular alkene insertion, and alkyl iodide reductive elimination, has been proposed and eventually supported by convincing evidence from a series of control experiments. More importantly, these control experiments disclose some features of the event of alkyl iodide reductive elimination: (1) this reductive elimination is proved to be a stereospecific process; and (2) both alkyl iodide oxidative addition and reductive elimination are not effected by a TEMPO additive. Besides its ability to undergo oxidative addition, the catalyst (palladium + DPPF) could also promote a radical transfer process. The findings described in this paper will be helpful for further development of the metal-catalyzed formation of a carbon-halide bond. © 2011 American Chemical Society.


Wang X.,Shanghai University | Han K.,Shanghai University | Li J.,Shanghai University | Jia X.,Shanghai University | And 2 more authors.
Polymer Chemistry | Year: 2013

A novel supramolecular alternating copolymer with [c2]daisy-chain dimer and macrocycle host dimer as repeating units has been fabricated. A key factor for this new assembly strategy is based on a [c2]daisy-chain pseudorotaxane bearing additional unbound recognition sites at both ends, which was successfully achieved from a careful designed heterotritopic (AB2-type) copillar[5]arene. By utilizing the intermolecular host-guest interactions between the double-threaded dimer and a pillar[5]arene dimer, a linear supramolecular polymer was prepared. These results provided not only a convenient approach for the construction of [c2]daisy chain based supramolecular polymers, but also a novel method for building supramolecular alternating copolymers. This journal is © The Royal Society of Chemistry.


Yang X.,CAS Beijing National Laboratory for Molecular
ACS Catalysis | Year: 2014

A density functional theory study of the reaction mechanism of the production of H2 and CO2 from methanol and water catalyzed by an aliphatic PNP pincer ruthenium complex, (PNP)Ru(H)CO, reveals three interrelated catalytic cycles for the release of three H2 molecules: the dehydrogenation of methanol to formaldehyde, the coupling of formaldehyde and hydroxide for the formation of formic acid, and the dehydrogenation of formic acid. The formation of all three H2 molecules undergoes the same self-promoted mechanism that features a methanol or a water molecule acting as a bridge for the transfer of a ligand proton to the metal hydride in a key intermediate, trans-(HPNP)Ru(H)2CO. © 2014 American Chemical Society.


Anthony J.E.,University of Kentucky | Facchetti A.,Polyera Corporation | Heeney M.,Imperial College London | Marder S.R.,Georgia Institute of Technology | Zhan X.,CAS Beijing National Laboratory for Molecular
Advanced Materials | Year: 2010

Organic semiconductors have been the subject of intensive academic and commercial interest over the past two decades, and successful commercial devices incorporating them are slowly beginning to enter the market. Much of the focus has been on the development of hole transporting, or p-type, semiconductors that have seen a dramatic rise in performance over the last decade. Much less attention has been devoted to electron transporting, or so called n-type, materials, and in this paper we focus upon recent developments in several classes of n-type materials and the design guidelines used to develop them. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA.


Zhang X.,Wuhan University | Yu L.,Wuhan University | Zhuang C.,Wuhan University | Peng T.,Wuhan University | And 2 more authors.
ACS Catalysis | Year: 2014

Highly asymmetric zinc phthalocyanine derivative (Zn-tri-PcNc) with intense near-IR light (650-800 nm) absorption is utilized as a sensitizer to extend the spectral response region of graphitic carbon nitride (g-C3N 4) from ∼450 nm to more than 800 nm. Ultraviolet-visible light (UV-vis) diffuse reflectance absorption spectra (DRS), photoluminescence (PL) spectra, time-resolved photoluminescence spectra (TRPS), and energy band structure analyses are adopted to investigate the photogenerated electron transfer process between Zn-tri-PcNc and g-C3N4 on both thermodynamics and dynamics aspects. After optimizing the photocatalytic condition and adding chenodeoxycholic acid (CDCA) as coadsorbent, Zn-tri-PcNc sensitized g-C3N4 photocatalyst shows a H2 production efficiency of 125.2 μmol h-1 under visible/near-IR- light (λ ≥ 500 nm) irradiation, corresponding to a turnover number (TON) of 5008 h-1 with an extremely high apparent quantum yield (AQY) of 1.85% at 700 nm monochromatic light irradiation. The present work should be the rarely fundamental investigation on the utilization of near-IR light of solar radiation for the photocatalytic H2 production from water splitting over a dye-sensitized semiconductor. © 2013 American Chemical Society.


Jiang H.,CAS Beijing National Laboratory for Molecular | Gomez-Abal R.I.,Fritz Haber Institute | Rinke P.,Fritz Haber Institute | Scheffler M.,Fritz Haber Institute
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

First-principles modeling of systems with localized d states is currently a great challenge in condensed-matter physics. Density-functional theory in the standard local-density approximation (LDA) proves to be problematic. This can be partly overcome by including local Hubbard U corrections (LDA+U) but itinerant states are still treated on the LDA level. Many-body perturbation theory in the GW approach offers both a quasiparticle perspective (appropriate for itinerant states) and an exact treatment of exchange (appropriate for localized states), and is therefore promising for these systems. LDA+U has previously been viewed as an approximate GW scheme. We present here a derivation that is simpler and more general, starting from the static Coulomb-hole and screened exchange approximation to the GW self-energy. Following our previous work for f -electron systems we conduct a systematic investigation of the GW method based on LDA+U (GW@LDA+U), as implemented in our recently developed all-electron GW code FHI-gap (Green's function with augmented plane waves) for a series of prototypical d -electron systems: (1) ScN with empty d states, (2) ZnS with semicore d states, and (3) late transition-metal oxides (MnO, FeO, CoO, and NiO) with partially occupied d states. We show that for ZnS and ScN, the GW band gaps only weakly depend on U but for the other transition-metal oxides the dependence on U is as strong as in LDA+U. These different trends can be understood in terms of changes in the hybridization and screening. Our work demonstrates that GW@LDA+U with "physical" values of U provides a balanced and accurate description of both localized and itinerant states. © 2010 The American Physical Society.


Wang M.-X.,Tsinghua University | Wang M.-X.,CAS Beijing National Laboratory for Molecular
Topics in Organometallic Chemistry | Year: 2011

Enantioselective biotransformations of nitriles using nitrile hydrolyzing microbial whole cell catalysts are a powerful method for the synthesis of highly enantioenriched carboxylic acids and amide derivatives. In this article, progress of Rhodococcus erythropolis AJ270-catalyzed enantioselective biotransformations of nitriles including various functionalized nitriles, α-and β-amino nitriles and β-hydroxy nitriles, cyclopropane-, oxirane-, aziridine-and azetidine-containing carbonitriles is summarized. Applications of enantioselective biotransformations of these nitriles in the synthesis of natural and bioactive products are also discussed. © 2011 Springer-Verlag Berlin Heidelberg.


Liu M.,CAS National Center for Nanoscience and Technology | Zheng Y.,Beihang University | Zhai J.,Beihang University | Jiang L.,CAS Beijing National Laboratory for Molecular | Jiang L.,Beihang University
Accounts of Chemical Research | Year: 2010

(Figure Presented) Super-antiwetting interfaces, such as superhydrophobic and superamphiphobic surfaces in air and superoleophobic interfaces in water, with special liquid-solid adhesion have recently attracted worldwide attention. Through tuning surface microstructures and compositions to achieve certain solid/liquid contact modes, we can effectively control the liquid-solid adhesion in a super-antiwetting state. In this Account, we review our recent progress in the design and fabrication of these bioinspired super-antiwetting interfaces with special liquid-solid adhesion. Low-adhesion superhydrophobic surfaces are biologically inspired, typically by the lotus leaf. Wettability investigated at microand nanoscale reveals that the low adhesion of the lotus surface originates from the composite contact mode, a microdroplet bridging several contacts, within the hierarchical structures. Recently high-adhesion superhydrophobic surfaces have also attracted research attention. These surfaces are inspired by the surfaces of gecko feet and rose petals. Accordingly, we propose two biomimetic approaches for the fabrication of high-adhesion superhydrophobic surfaces. First, to mimic a sticky gecko's foot, we designed structures with nanoscale pores that could trap air isolated from the atmosphere. In this case, the negative pressure induced by the volume change of sealed air as the droplet is pulled away from surface can produce a normal adhesive force. Second, we constructed microstructures with size and topography similar to that of a rose petal. The resulting materials hold air gaps in their nanoscale folds, controlling the superhydrophobicity in a Wenzel state on the microscale. Furthermore, we can tune the liquid-solid adhesion on the same superhydrophobic surface by dynamically controlling the orientations of microstructures without altering the surface composition. The superhydrophobic wings of the butterfly (Morpho aega) show directional adhesion: a droplet easily rolls off the surface of wings along one direction but is pinned tightly against rolling in the opposite direction. Through coordinating the stimuli-responsive materials and appropriate surface-geometry structures, we developed materials with reversible transitions between a low-adhesive rolling state and a high-adhesive pinning state for water droplets on the superhydrophobic surfaces, which were controlled by temperature and magnetic and electric fields. In addition to the experiments done in air, we also demonstrated bioinspired superoleophobic water/solid interfaces with special adhesion to underwater oil droplets and platelets. In these experiments, the high content of water trapped in the micro- and nanostructures played a key role in reducing the adhesion of the oil droplets and platelets. These findings will offer innovative insights into the design of novel antibioadhesion materials. © 2010 American Chemical society.


Zhang W.,CAS Suzhou Institute of Nano Technology and Nano Bionics | Zhu Y.,CAS Suzhou Institute of Nano Technology and Nano Bionics | Liu X.,CAS Suzhou Institute of Nano Technology and Nano Bionics | Wang D.,CAS Suzhou Institute of Nano Technology and Nano Bionics | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2014

Conventional polymer membranes suffer from low flux and serious fouling when used for treating emulsified oil/water mixtures. Reported herein is the fabrication of a novel superhydrophilic and underwater superoleophobic poly(acrylic acid)-grafted PVDF filtration membrane using a salt-induced phase-inversion approach. A hierarchical micro/nanoscale structure is constructed on the membrane surface and endows it with a superhydrophilic/ underwater superoleophobic property. The membrane separates both surfactant-free and surfactant-stabilized oil-in-water emulsions under either a small applied pressure (<0.3 bar) or gravity, with high separation efficiency and high flux, which is one to two orders of magnitude higher than those of commercial filtration membranes having a similar permeation property. The membrane exhibits an excellent antifouling property and is easily recycled for long-term use. The outstanding performance of the membrane and the efficient, energy and cost-effective preparation process highlight its potential for practical applications. Salting away: The title membranes having different PAA graft ratios were fabricated by using a salt-induced phase-inversion process. The membrane can separate both surfactant-free and surfactant-stabilized oil-in-water emulsions under either a small applied pressure (0.1 bar) or gravity, with a high separation efficiency and high flux. CA=contact angle. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Liu K.,Beihang University | Jiang L.,Beihang University | Jiang L.,CAS Beijing National Laboratory for Molecular
Nano Today | Year: 2011

Multiscale structures of biological materials exhibit inherent multifunctional integration. This special biological solution provides some inspiration for scientists and engineers to design multifunctional artificial materials with multiscale structures. In this review, we focus on recent research progress in some typical biological materials (such as lotus leaves, rice leaves, butterfly wings, water strider legs, insect compound eyes, fish scales, red rose petals, brittlestars, spider silks, nacre, glass sponges, gecko feet, mussels, and others) and the corresponding bio-inspired multiscale materials possessing function integration. The challenges and perspectives for bio-inspired design of multifunctional structures in the future are also briefly addressed. © 2011 Elsevier Ltd. All rights reserved.


Zhang Y.,CAS Institute of Chemistry | Yuan X.,CAS Institute of Chemistry | Wang Y.,CAS Institute of Chemistry | Chen Y.,CAS Institute of Chemistry | And 2 more authors.
Journal of Materials Chemistry | Year: 2012

A one-step photochemical approach was established to quickly and specifically synthesize uniformly dispersed silver nanoparticles (AgNPs) on reduced graphene oxide (rGO) nanosheets. Silver-ammonia and graphene oxide (GO) were used as precursors to enhance the coordination-based adsorption of silver cations onto the negatively charged GO surface through ligation with ammonia, which could also continuously stabilize the nucleation and growth of AgNPs. The method allowed the easy control of the coverage percentage of AgNPs on rGO in a range from 7.2% to 81.6%. The prepared AgNPs-rGO composites were highly dispersible and stable in water in the absence of any stabilizing agent, and showed excellent catalytic properties in the reduction of 2-nitroaniline to 1,2-benzenediamine. © 2012 The Royal Society of Chemistry.


Li Y.,East China Normal University | Pu J.,East China Normal University | Jiang X.,East China Normal University | Jiang X.,CAS Beijing National Laboratory for Molecular | Jiang X.,Nankai University
Organic Letters | Year: 2014

A highly efficient Cu-catalyzed dual C-S bonds formation reaction, proceeding in alcohol and water under air, is reported, in which inodorous stable Na2S2O3 is used as a sulfurating reagent. This powerful strategy provides a practical and efficient approach to construct thioethers, using readily available aromatic amines and alkyl halides as starting materials. Sensitive and synthetic useful functional groups could be tolerated. Furthermore, pharmaceuticals, glucose, an amino acid, and a chiral ligand are successfully furnished by this late-stage sulfuration strategy. © 2014 American Chemical Society.


Zhang X.,Hunan Normal University | Zeng W.,Hunan Normal University | Yang Y.,Hunan Normal University | Huang H.,Hunan Normal University | And 2 more authors.
Organic Letters | Year: 2014

A new, highly efficient procedure for the synthesis of benzothiazoles from easily available N-benzyl-2-iodoaniline and potassium sulfide has been developed. The results show copper-catalyzed double C-S bond formation via a traditional cross-coupling reaction and an oxidative cross-coupling reaction. © 2014 American Chemical Society.


Zhan X.,CAS Beijing National Laboratory for Molecular | Facchetti A.,Northwestern University | Facchetti A.,Polyera Corporation | Barlow S.,Georgia Institute of Technology | And 4 more authors.
Advanced Materials | Year: 2011

Organic electron-transporting materials are essential for the fabrication of organic p-n junctions, photovoltaic cells, n-channel field-effect transistors, and complementary logic circuits. Rylene diimides are a robust, versatile class of polycyclic aromatic electron-transport materials with excellent thermal and oxidative stability, high electron affinities, and, in many cases, high electron mobilities; they are, therefore, promising candidates for a variety of organic electronics applications. In this review, recent developments in the area of high-electron-mobility diimides based on rylenes and related aromatic cores, particularly perylene- and naphthalene-diimide-based small molecules and polymers, for application in high-performance organic field-effect transistors and photovoltaic cells are summarized and analyzed. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zhang X.,Beihang University | Li Z.,Beihang University | Liu K.,Beihang University | Jiang L.,Beihang University | Jiang L.,CAS Beijing National Laboratory for Molecular
Advanced Functional Materials | Year: 2013

Oil/water separation is a worldwide challenge. Learning from nature provides a promising approach for the construction of functional materials with oil/water separation. In this contribution, inspired by superhydrophobic self-cleaning lotus leaves and porous biomaterials, a facile method is proposed to fabricate polyurethane foam with simultaneous superhydrophobicity and superoleophilicity. Due to its low density, light weight, and superhydrophobicity, the as-prepared foam can float easily on water. Furthermore, the foam demonstrates super-repellency towards corrosive liquids, self-cleaning, and oil/water separation properties, possessing multifunction integration. We expect that this low-cost process can be readily and widely adopted for the design of multifunctional foams for large-area oil-spill cleanup. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Meng J.,CAS Technical Institute of Physics and Chemistry | Zhang P.,CAS Beijing National Laboratory for Molecular | Wang S.,CAS Technical Institute of Physics and Chemistry
Chemical Society Reviews | Year: 2016

Abrasion-resistant materials have attracted great attention for their broad applications in industry, biomedicine and military. However, the development of abrasion-resistant materials that have with unique features such as being lightweight and flexible remains a great challenge in order to satisfy unmet demands. The outstanding performance of natural abrasion-resistant materials motivates the development of new bio-inspired abrasion-resistant materials. This review summarizes the recent progress in the investigation of natural abrasion-resistant materials to explore their general design principles (i.e., the correlation between chemical components and structural features). Following natural design principles, several artificial abrasion-resistant materials have shown unique abrasion-resistant properties. The potential challenges in the future and possible solutions for designing bio-inspired abrasion-resistant materials are also briefly discussed. © The Royal Society of Chemistry.


Feng T.,CAS Beijing National Laboratory for Molecular
The Analyst | Year: 2013

A new approach is proposed for simple detection of adenosine deaminase (ADA) based on adenosine induced self-assembly of two pieces of single-stranded DNA (ssDNA). These ssDNA are two fragments of the aptamer that has a strong affinity for adenosine and are labeled with carboxyfluorescein and black hole quencher-1, respectively. The complementarities of the bases in the two pieces of ssDNA are insufficient to form a stable structure. In the presence of adenosine, however, the ssDNA can be assembled into the intact aptamer tertiary structure, which results in fluorescence quenching of the carboxyfluorescein-labeled aptamer fragment. As a result, the adenosine-ssDNA complex shows a low background signal, which is rather desired for achieving sensitive detection. Reaction of the complex with ADA causes a great fluorescence enhancement by converting adenosine into inosine that has no affinity for the aptamer. This behaviour leads to the development of a simple and sensitive fluorescent method for assaying ADA activity, with a detection limit of 0.05 U mL(-1), which is more sensitive than most of the existing approaches. Furthermore, the applicability of the method has been demonstrated by detecting ADA in mouse serum samples.


Cheng H.,CAS Beijing National Laboratory for Molecular
The Analyst | Year: 2013

This study demonstrates a new electrochemical method for continuous neurochemical sensing with a biofuel cell-based self-powered biogenerator as the detector for the analysis of microdialysate continuously sampled from rat brain, with glucose as an example analyte. To assemble a glucose/O(2) biofuel cell that can be used as a self-powered biogenerator for glucose sensing, glucose dehydrogenase (GDH) was used as the bioanodic catalyst for the oxidation of glucose with methylene green (MG) adsorbed onto single-walled carbon nanotubes (SWNTs) as the electrocatalyst for the oxidation of dihydronicotinamide adenine dinucleotide (NADH). Laccase crosslinked onto SWNTs was used as the biocathodic catalyst for the O(2) reduction. To enable the bioanode and biocathode to work efficiently in their individually favorable solutions and to eliminate the interference between the glucose bioanode and O(2) biocathode, the biofuel cell-based biogenerator was built in a co-laminar microfluidic chip so that the bioanodic and biocathodic streams could be independently optimized to provide conditions favorable for each of the bioelectrodes. By using a home-made portable voltmeter to output the voltage generated on an external resistor, the biogenerator was used for glucose sensing based on a galvanic cell mechanism. In vitro experiments demonstrate that, under the optimized conditions, the voltage generated on an external resistor shows a linear relationship with the logarithmic glucose concentration within a concentration range of 0.2 mM to 1.0 mM. Moreover, the biogenerator exhibits a high stability and a good selectivity for glucose sensing. The validity of the biofuel cell-based self-powered biogenerator for continuous neurochemical sensing was illustrated by online continuous monitoring of striatum glucose in rat brain through the combination of in vivo microdialysis. This study offers a new and technically simple platform for continuously monitoring physiologically important species in cerebral systems.


Liang K.,CAS Institute of Chemistry | Chen Y.,CAS Institute of Chemistry | Chen Y.,CAS Beijing National Laboratory for Molecular
Bioconjugate Chemistry | Year: 2012

An easy chemical strategy was proposed and used to establish a method for direct anchoring of intact saccharides on solid surfaces with well conserved bioaffinity. The anchoring was achieved by temperature-modulated stepwise reactions with cyanuric chloride as a key linker, and was successfully applied to the fabrication of saccharide chips. To demonstrate, 15 intact reducing and nonreducing saccharides with various molecular sizes were dotted on a cyanuric-chloride-modified chip (1.0 × 1.0 cm2) and made to react with lectins. As expected, the anchored saccharides were capable of recognizing their target lectins, and more exciting were the perfect conservation of the specific recognizing ability of the anchored monosaccharides such as mannose, glucose, and even fructose (interacting only weakly with concanavalin A). This conservation was ascribed to the maintenance of the original structure (especially the anomeric configuration) of saccharides after immobilization and to the allowance of the anchored saccharides to rotate with and/or on the scaffold of cyanuric chloride, which makes them easily adapt to the recognition-preferred spatial position. The expected linkage of saccharides on cyanuric chloride and the maintenance of their anomeric configuration were characterized by mass spectrometry and nuclear magnetic resonance, respectively. The new method can be highlighted not only by its conservation of saccharide bioaffinity and universal applicability but also by its merits of easy manipulation or facile control of the reactions and cost-effectiveness due to the use of extremely cheap cyanuric chloride. (Chemical Equation Presented) © 2012 American Chemical Society.


Liu W.,CAS Beijing National Laboratory for Molecular
Molecular Physics | Year: 2010

The basic ideas of relativistic quantum chemistry are highlighted, with the most important ingredients summarised as follows. (1) The restricted kinetic balance (RKB) condition, being both necessary and sufficient, serves as the cornerstone for the matrix representation of the Dirac-based Hamiltonian. (2) The concept of matrix transformation plays the key role in formulating two-component relativistic theories. Some popular ones, albeit presented as operators, are de facto matrix formulations in terms implicitly of the RKB condition. They merely make simple things complicated as a one-step block-diagonalization of the matrix Dirac equation can do the whole job. (3) The computational efficiency for both four- and two-component relativistic theories can be gained by means of the simple chemical idea of 'from atoms to molecule' without recourse to mathematical tricks. The two branches of relativistic theories have thus been made fully equivalent in all the aspects of simplicity, accuracy, and efficiency. It is concluded that the best relativistic electrons-only Hamiltonian has been found, which can be combined with any know-how correlation methods for electronic structure calculations of all the atoms in the Periodic Table. Most amazingly, the new quantum mechanical equation serves as a seamless bridge between the Schrodinger and Dirac equations. In short, the 'relativity problem' in chemistry has been solved. © 2010 Taylor & Francis.


Du X.,Beijing Institute of Technology | Liu H.,CAS Beijing National Laboratory for Molecular | Du D.-M.,Beijing Institute of Technology
European Journal of Organic Chemistry | Year: 2011

Diphenyl sulfide linked bis(imidazoline) ligands with electron-withdrawing N-Ts substitution and electron-donating N-alkyl or N-H substitutions were synthesized through different routes. The electronic effects of the ligands were tuned rationally, and dramatic variation in their catalytic behavior was observed. N-Alkyl and N-H ligands demonstrated much higher catalytic activity and improved enantioselectivity than N-Ts ligands in Pd-catalyzed asymmetric allylic alkylation reactions. Diphenyl sulfide linked bis(imidazoline) ligands were synthesized. The electronic effects of the ligands were tuned rationally, and dramatic variation in their catalytic behavior was observed. N-Alkyl and N-H ligands showed much higher catalytic activity and improved enantioselectivity over N-Ts ligands in Pd-catalyzed asymmetric allylic alkylation reactions. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Van Franeker J.J.,TU Eindhoven | Turbiez M.,TU Eindhoven | Turbiez M.,Dutch Polymer Institute | Li W.,BASF | And 4 more authors.
Nature Communications | Year: 2015

The photoactive layer of organic solar cells consists of a nanoscale blend of electron-donating and electron-accepting organic semiconductors. Controlling the degree of phase separation between these components is crucial to reach efficient solar cells. In solution-processed polymer-fullerene solar cells, small amounts of co-solvents are commonly used to avoid the formation of undesired large fullerene domains that reduce performance. There is an ongoing discussion about the origin of this effect. To clarify the role of co-solvents, we combine three optical measurements to investigate layer thickness, phase separation and polymer aggregation in real time during solvent evaporation under realistic processing conditions. Without co-solvent, large fullerene-rich domains form via liquid-liquid phase separation at ∼20 vol% solid content. Under such supersaturated conditions, co-solvents induce polymer aggregation below 20 vol% solids and prevent the formation of large domains. This rationalizes the formation of intimately mixed films that give high-efficient solar cells for the materials studied. © 2015 Macmillan Publishers Limited. All rights reserved.


Zhang Z.,East China Normal University | Jiang X.,East China Normal University | Jiang X.,CAS Beijing National Laboratory for Molecular
Organic Letters | Year: 2014

An efficient and mild copper-catalyzed one-pot approach toward ynediones has been established. A variety of ynediones were constructed directly through oxidative coupling of alkyne with α-hydroxy ketone. Oxygen-oxidizing and neutral conditions in one-pot for a wide range of substrates including natural product derivatives make this transformation highly efficient and practical. On the basis of control experiments, in situ IR measurements, and isotopic labeling experiments, a plausible mechanism involving intermediate phenylglyoxal was drawn. Applications by synthesis of various heterocycles were also investigated. © 2014 American Chemical Society.


Hu F.,Beijing Normal University | Zhao Y.S.,CAS Beijing National Laboratory for Molecular
Nanoscale | Year: 2012

Magnetic resonance imaging (MRI) yields high spatially resolved contrast with anatomical details for diagnosis, deeper penetration depth and rapid 3D scanning. To improve imaging sensitivity, adding contrast agents accelerates the relaxation rate of water molecules, thereby greatly increasing the contrast between specific issues or organs of interest. Currently, the majority of T 1 contrast agents are paramagnetic molecular complexes, typically Gd(iii) chelates. Various nanoparticulate T 1 and T 1/T 2 contrast agents have recently been investigated as novel agents possessing the advantages of both the T 1 contrast effect and nanostructural characteristics. In this minireview, we describe the recent progress of these inorganic nanoparticle-based MRI contrast agents. Specifically, we mainly report on Gd and Mn-based inorganic nanoparticles and ultrasmall iron oxide/ferrite nanoparticles. This journal is © 2012 The Royal Society of Chemistry.


Rui H.,Peking University | Xing R.,Peking University | Xu Z.,Brown University | Xu Z.,Massachusetts Institute of Technology | And 3 more authors.
Advanced Materials | Year: 2010

Synthesis of multifunctional magnetic nanoparticles (MFMNPs) is one of the most active research areas in advanced materials. MFMNPs that have magnetic properties and other functionalities have been demonstrated to show great promise as multimodality imaging probes. Their multifunctional surfaces also allow rational conjugations of biological and drug molecules, making it possible to achieve target-specific diagnostics and therapeutics. This review first outlines the synthesis of MNPs of metal oxides and alloys and then focuses on recent developments in the fabrication of MFMNPs of core/shell, dumbbell, and composite hybrid type. It also summarizes the general strategies applied for NP surface functionalization. The review further highlights some exciting examples of these MFMNPs for multimodality imaging and for target-specific drug/gene delivery applications. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Yang W.,Beijing Institute of Technology | Liu H.,CAS Beijing National Laboratory for Molecular | Du D.-M.,Beijing Institute of Technology
Organic and Biomolecular Chemistry | Year: 2010

A combinatorial in situ three-component chiral oxazoline-Schiff base copper(ii) complex catalyst formation method was developed. This simple combinatorial chiral catalyst approach provided a modular library of chiral oxazoline-Schiff base copper(ii) complex catalysts. The catalytic activity of these in situ generated catalysts can be rapidly and conveniently evaluated in the asymmetric Henry reaction. Moderate to good yields and enantioselectivities (up to 92% ee) were obtained under the optimized condition. The combination of modular three-component catalyst formation and in situ asymmetric reaction provides a new technology in asymmetric catalysis. © 2010 The Royal Society of Chemistry.


Bai C.,CAS Institute of Chemistry | Liu M.,CAS Beijing National Laboratory for Molecular
Nano Today | Year: 2012

Nanomaterials and nanostructures implanted on the surface of solid supports are currently receiving much interest and have become one of the most attractive topics in the interdisciplinary fields of nanoscience and nanotechnology, surface science, material science, bioscience, supramolecular engineering, etc. This review presents some recent progress in how to implant the nanomaterials and nanostructures such as nanoparticles, nanowires, nanotubes and chiral nanostructures on the surface of certain supports and their potential application opportunities. It particularly focused on several sophisticated and typical strategies for the formulation of nanostructured surface, wherein the unique physicochemical and biochemical properties and potential application possibilities emerged. An outlook on the future trends and developments in this area is also proposed at the end of the article. © 2012 Elsevier Ltd. All rights reserved.


Xi Z.,CAS Beijing National Laboratory for Molecular
Accounts of Chemical Research | Year: 2010

The development of organometallic reagents remains one of the most important frontiers in synthetic chemistry. Commonly used organometallic reagents (such as RLi and RMgBr) are typically monometallic compounds, although they aggregate in many cases. When two carbon-metal bonds are in the same molecule in close proximity, however, these two carbon-metal moieties may exhibit novel reactivity. In this Account, we outline our work on new reactions and synthetic applications of the organo-dilithio reagents 1,4-dilithio-1,3- butadienes. The 1,4-dilithio-1,3-butadienes can be accessed readily in high efficiency with a wide variety of substitution patterns on the butadienyl skeleton. The configuration has been predicted and demonstrated to favor a double dilithium bridging structure in both solution and solid states. The two Li atoms are bridged by a butadiene moiety and are in close proximity. By taking advantage of this unique configuration, we have developed useful and interesting synthetic methodologies. Three types of reactions of 1,4-dilithio-1,3-butadienes, termed dilithio reagents here, have been developed and are discussed. An intramolecular reaction is introduced in the first section. The reaction is a result of the intracooperative effect among the two C-Li moieties, the butadienyl bridge, and the substituents. A useful transformation from silylated 1,4-dilithio-1,3-butadienes to α-lithio siloles is described. Second, we discuss an intermolecular reaction that results from the intercooperative effect of the two C-Li moieties toward substrates. As an example of the formation of functionalized cyclic dianions from the linear dianions of the dilithio reagents and organic substrates, we describe the isolation and structural characterization of a novel type of cyclic dianion; that is, fully substituted oxy-cyclopentadienyl dilithium formed via the reaction of dilithio reagents with CO. We also describe diverse reactions of dilithio reagents with nitriles to form substituted pyridines, tricyclic 1-bipyrrolines, and siloles, demonstrating the remarkable effect of substituents on the butadienyl skeleton. Third, we discuss transmetalation of dilithio reagents to generate other organo-dimetallic compounds. This section focuses on organo-dicopper compounds and their reactivity toward the synthesis of strained ring systems, such as semibullvalenes and twisted four-membered rings, with the metal-mediated C-C bond-forming approach. In addition to these three representative reactions, other useful applications are also briefly introduced. The dimetallic 1,4-dilithio-1,3-butadienes and their transmetalated derivatives provide unique synthetic organometallic reagents that are very different from monometallic reagents, both in terms of reactivity and synthetic application. These organo-dimetallic reagents provide access to interesting and useful compounds that are not available by other means. Moreover, given the possibilities afforded, the study of organo-dimetallic and organo-polymetallic compounds should yield further synthetic applications in the near future. © 2010 American Chemical Society.


Zhang X.,Tsinghua University | Liu M.,CAS Beijing National Laboratory for Molecular | Yang B.,Tsinghua University | Wei Y.,Tsinghua University
Colloids and Surfaces B: Biointerfaces | Year: 2013

Tetraphenylethene-based (TPE) aggregation-induced emission fluorescent organic nanoparticles (FONs) were facilely prepared via Schiff base condensation with e{open}-polylysine (Ply) and subsequent reduction to form stable C. N covalent bond. Thus obtained TPE-Ply FONs were characterized by a series of techniques including fluorescent spectroscopy, Fourier transform infrared spectroscopy and transmission electron microscopy. Biocompatibility evaluation and cell uptake behavior of TPE-Ply FONs were further investigated to explore their potential biomedical application. We demonstrated that such FONs showed high water dispersibility, intense fluorescence, uniform morphology (100-200. nm) and excellent biocompatibility, making them promising for cell imaging application. © 2013 Elsevier B.V.


Peng T.,Wuhan University | Zhang X.,Wuhan University | Zeng P.,Wuhan University | Li K.,Wuhan University | Li X.,CAS Beijing National Laboratory for Molecular
Journal of Catalysis | Year: 2013

Carbon encapsulation strategy of Ni co-catalyst is applied to the fabrication of novel carbon-coated Ni (Ni@C)/CdS nanocomposite photocatalyst with high efficiency and good stability via a facile solvothermal process by using a pre-prepared Ni@C as a starting material. It is found that the metallic Ni nanoparticles encapsulated in the graphite-like carbon shells show a high chemical and thermal stability, and the resultant Ni@C/CdS nanocomposite shows an average photocatalytic H2-production activity of 622.7 μmol h-1 during 5-h visible-light irradiation and an apparent quantum yield up to ca. 20.5% under 420 nm monochromatic light irradiation. The metallic Ni in Ni@C acted as co-catalyst while the graphite-like carbon as CdS nanoparticles' support and electron acceptor, which resulting in the efficient charge separation, and then the enhanced photoactivity and stability for H 2 production as compared to the pristine CdS nanoparticles. The present novel carbon encapsulation strategy of Ni co-catalyst can shed light on the fabrication of new cheap photocatalyst with excellent photoactivity and stability for H2 production.© 2013 Elsevier Inc. All rights reserved.


Xue Z.-X.,CAS Beijing National Laboratory for Molecular | Jiang L.,CAS Beijing National Laboratory for Molecular
Acta Polymerica Sinica | Year: 2012

Underwater superoleophobic surfaces are surfaces that display contact angle with oil droplets larger than 150° in oil/water/solid three-phase system. In this review two typical biological surfaces which own excellent superoleophobic property in water,the fish scales and lower side of lotus leaf were introduced. The key factors influencing the underwater superoleophobicity were discussed and concluded. Based on this, a design route of constructing underwater superoleophobic systems was raised. Then the fabrication approaches and recent developments of underwater superoleophobic surfaces were introduced. The intelligent underwater superoleophobic surfaces with stimuli-responsive wettability and oil adhesion were summed up briefly. The applications of underwater superoleophobic surfaces,such as oil droplets manipulation,anti- bioadhesion and oil water separation, were introduced. At the end of this review, the challenges and future developments of underwater superoleophobic system were discussed.


Gu J.,CAS Beijing National Laboratory for Molecular | Zhang Y.-W.,CAS Beijing National Laboratory for Molecular | Tao F.,University of Notre Dame
Chemical Society Reviews | Year: 2012

Synthesis of bimetallic nanomaterials with well controlled shape is an important topic in heterogeneous catalysis, low-temperature fuel cell technology, and many other fields. Compared with monometallic counterparts, bimetallic nanocatalysts endow scientists with more opportunities to optimize the catalytic performance by modulating the charge transfer between different metals, local coordination environment, lattice strain and surface element distribution. Considering the current challenges in shape controlled synthesis of bimetallic nanocatalysts, this tutorial review highlights some significant achievements in preparing bimetallic alloy, core-shell and heterostructure nanocrystals with well-defined morphologies, summarizes four general routes and some key factors of the bimetallic shape control scenarios, and provides some general ideas on how to design synthetic strategies to control the shape and exposing facets of bimetallic nanocrystals. The composition and shape dependent catalytic behaviours of bimetallic nanocrystals are reviewed as well. © 2012 The Royal Society of Chemistry.


Jin Z.,CAS Beijing National Laboratory for Molecular | Jin Z.,University of Chinese Academy of Sciences | Wang J.,CAS Beijing National Laboratory for Molecular
Journal of Materials Chemistry C | Year: 2013

We designed and fabricated an inorganic-organic hybrid bilayer thin film photoconductor. The advantages of the organic material's strong light absorption ability and the inorganic material's high carrier mobility are combined; a high responsivity (R) value of 11 101 A W-1 is achieved, which is much higher than that of present pure inorganic and pure organic thin-film photoconductors. © 2013 The Royal Society of Chemistry.


Su J.,CAS Beijing National Laboratory for Molecular | Guo H.,CAS Beijing National Laboratory for Molecular
Journal of Physical Chemistry B | Year: 2013

Inspired by the importance of charged nanoparticles (NPs) in biomedicine and their potential applications in nanofluids, we analyze the translocation of cationic and anionic nanoparticles through a nanochannel by explicit solvent molecular dynamics simulations. We focus on the interplay of NPs and ions. The cations bind to the anionic NPs much more than the anions to the cationic NPs, which in turn affects the flux behavior. In particular, the nanochannel enhances the difference between cationic and anionic NPs during the translocation process. With the increase of salt concentration, the ion flux increases nonlinearly with external field strength, in agreement with recent experimental observations, while the NP flux decreases, which suggests a nontrivial competition between the translocation of ions and NPs. Our results revealed the important role of ions during the NP translocation and may have implications in the detection, separation, and filtration of charged NPs. © 2013 American Chemical Society.


Liu K.,Beihang University | Jiang L.,Beihang University | Jiang L.,CAS Beijing National Laboratory for Molecular
Annual Review of Materials Research | Year: 2012

Self-cleaning surfaces have drawn a lot of interest for both fundamental research and practical applications. This review focuses on the recent progress in mechanism, preparation, and application of self-cleaning surfaces. To date, self-cleaning has been demonstrated by the following four conceptual approaches: (a) TiO2-based superhydrophilic self-cleaning, (b) lotus effect self-cleaning (superhydrophobicity with a small sliding angle), (c) gecko setaeinspired self-cleaning, and (d) underwater organismsinspired antifouling self-cleaning. Although a number of self-cleaning products have been commercialized, the remaining challenges and future outlook of self-cleaning surfaces are also briefly addressed. Through evolution, nature, which has long been a source of inspiration for scientists and engineers, has arrived at what is optimal. We hope this review will stimulate interdisciplinary collaboration among material science, chemistry, biology, physics, nanoscience, engineering, etc., which is essential for the rational design and reproducible construction of bio-inspired multifunctional self-cleaning surfaces in practical applications. © Copyright ©2012 by Annual Reviews. All rights reserved.


Li Y.,CAS Beijing National Laboratory for Molecular
Accounts of Chemical Research | Year: 2012

Bulk heterojunction (BHJ) polymer solar cells (PSCs) sandwich a blend layer of conjugated polymer donor and fullerene derivative acceptor between a transparent ITO positive electrode and a low work function metal negative electrode. In comparison with traditional inorganic semiconductor solar cells, PSCs offer a simpler device structure, easier fabrication, lower cost, and lighter weight, and these structures can be fabricated into flexible devices. But currently the power conversion efficiency (PCE) of the PSCs is not sufficient for future commercialization. The polymer donors and fullerene derivative acceptors are the key photovoltaic materials that will need to be optimized for high-performance PSCs.In this Account, I discuss the basic requirements and scientific issues in the molecular design of high efficiency photovoltaic molecules. I also summarize recent progress in electronic energy level engineering and absorption spectral broadening of the donor and acceptor photovoltaic materials by my research group and others. For high-efficiency conjugated polymer donors, key requirements are a narrower energy bandgap (E g) and broad absorption, relatively lower-lying HOMO (the highest occupied molecular orbital) level, and higher hole mobility. There are three strategies to meet these requirements: D-A copolymerization for narrower E g and lower-lying HOMO, substitution with electron-withdrawing groups for lower-lying HOMO, and two-dimensional conjugation for broad absorption and higher hole mobility. Moreover, better main chain planarity and less side chain steric hindrance could strengthen Ï€-Ï€ stacking and increase hole mobility. Furthermore, the molecular weight of the polymers also influences their photovoltaic performance. To produce high efficiency photovoltaic polymers, researchers should attempt to increase molecular weight while maintaining solubility. High-efficiency D-A copolymers have been obtained by using benzodithiophene (BDT), dithienosilole (DTS), or indacenodithiophene (IDT) donor unit and benzothiadiazole (BT), thienopyrrole-dione (TPD), or thiazolothiazole (TTz) acceptor units. The BDT unit with two thienyl conjugated side chains is a highly promising unit in constructing high-efficiency copolymer donor materials. The electron-withdrawing groups of ester, ketone, fluorine, or sulfonyl can effectively tune the HOMO energy levels downward.To improve the performance of fullerene derivative acceptors, researchers will need to strengthen absorption in the visible spectrum, upshift the LUMO (the lowest unoccupied molecular orbital) energy level, and increase the electron mobility. [6,6]-Phenyl-C 71-butyric acid methyl ester (PC 70BM) is superior to [6,6]-phenyl-C 61-butyric acid methyl ester (PCBM) because C 70 absorbs visible light more efficiently. Indene-C 60 bisadduct (ICBA) and Indene-C 70 bisadduct (IC 70BA) show 0.17 and 0.19 eV higher LUMO energy levels, respectively, than PCBM, due to the electron-rich character of indene and the effect of bisadduct. ICBA and IC 70BA are excellent acceptors for the P3HT-based PSCs. © 2012 American Chemical Society.


Li B.-J.,CAS Beijing National Laboratory for Molecular | Shi Z.-J.,CAS Beijing National Laboratory for Molecular | Shi Z.-J.,Chinese Academy of Sciences
Chemical Society Reviews | Year: 2012

In this tutorial review, we will summarize our recent efforts in transition metal-catalyzed oxidative coupling via C-H functionalization of aromatic, benzylic and allylic C-H bonds. Related works from other laboratories will be cited where suitable, aiming to give the readers a flavor of this field. Special emphasis is placed on the reaction design and development. © The Royal Society of Chemistry 2012.


Ju J.,CAS Beijing National Laboratory for Molecular | Zheng Y.,Beihang University | Jiang L.,CAS Beijing National Laboratory for Molecular | Jiang L.,Beihang University
Accounts of Chemical Research | Year: 2014

ConspectusOne-dimensional materials (1D) capable of transporting liquid droplets directionally, such as spider silks and cactus spines, have recently been gathering scientists attention due to their potential applications in microfluidics, textile dyeing, filtration, and smog removal. This remarkable property comes from the arrangement of the micro- and nanostructures on these organisms surfaces, which have inspired chemists to develop methods to prepare surfaces with similar directional liquid transport ability. In this Account, we report our recent progress in understanding how this directional transport works, as well our advances in the design and fabrication of bioinspired 1D materials capable of transporting liquid droplets directionally.To begin, we first discuss some basic theories on droplet directional movement. Then, we discuss the mechanism of directional transport of water droplets on natural spider silks. Upon contact with water droplets, the spider silk undergoes what is known as a wet-rebuilt, which forms periodic spindle-knots and joints. We found that the resulting gradient of Laplace pressure and surface free energy between the spindle-knots and joints account for the cooperative driving forces to transport water droplets directionally. Next, we discuss the directional transport of water droplets on desert cactus. The integration of multilevel structures of the cactus and the resulting integration of multiple functions together allow the cactus spine to transport water droplets continuously from tip to base.Based on our studies of natural spider silks and cactus spines, we have prepared a series of artificial spider silks (A-SSs) and artificial cactus spines (A-CSs) with various methods. By changing the surface roughness and chemical compositions of the artificial spider silks spindle-knots, or by introducing stimulus-responsive molecules, such as thermal-responsive and photoresponsive molecules, onto the spindle-knots, we can reversibly manipulate the direction of water droplets movement on the prepared A-SSs. In addition, the A-SSs with nonuniform spindle-knots, such as multilevel sized spindle-knots and gradient spindle-knots, further demonstrate integrated directional transport ability for water droplets. Through mimicking the main principle of cactus spines in transporting water droplets, we were able to fabricate both single and array A-CSs, which are able to transport liquid droplets directionally both in air and under water.Lastly, we demonstrated some applications of this directional liquid transport, from aspects of efficient fog collection to oil/water separation. In addition, we showed some potential applications in smart catalysis, tracer substance enrichment, smog removal, and drug delivery. © 2014 American Chemical Society.


Meng Q.,CAS Beijing National Laboratory for Molecular | Hu W.,CAS Beijing National Laboratory for Molecular
Physical Chemistry Chemical Physics | Year: 2012

Substantial improvement of n-channel organic semiconductors has been realized after the research focus turned from hole transporting (p-type) organic semiconductors to electron-transporting (n-type) and ambipolar-transporting organic semiconductors. In this review, several novel n-type semiconducting small molecules, as well as promising developments of traditional systems, which were reported to exhibit high electron-transport performance in the last three years will be summarized. © 2012 the Owner Societies.


Zhang J.,CAS Beijing National Laboratory for Molecular | Shen X.,CAS Beijing National Laboratory for Molecular
Journal of Physical Chemistry B | Year: 2013

The vesicle is found to form in the concentrated aqueous solution of ionic liquid 1-dodecyl-3-methylimidazolium bromide (C12mimBr) and β-CD. By decreasing the temperature, the vesicle changes into a novel supramolecular hydrogel constructed from lamellae. The process is reversible and reproducible. The mechanism for the formation of vesicles and supramolecular hydrogel is studied by various methods. It is suggested that the main driving force is hydrogen bonding between β-CDs, β-CD and the solvent, the imidazolium headgroup of C12mim+, and the solvent. Accordingly, the basic structural features of the vesicle and supramolecular hydrogel based on ionic liquid and β-CD are illustrated. The structural evolution from vesicles to hydrogels is also discussed herein. © 2013 American Chemical Society.


Lei T.,CAS Beijing National Laboratory for Molecular | Pei J.,CAS Beijing National Laboratory for Molecular
Journal of Materials Chemistry | Year: 2012

Recently many efforts have been devoted to the investigation of organic nano- and micro-materials due to their unique properties and broad applications in organic field-effect transistors, organic light-emitting diodes, organic photovoltaics, photodetectors and superhydrophobic materials. In comparison with physical vapour deposition, solution processing provides a more convenient and cost-effective approach to obtain organic nano- and micro-materials with various morphologies, including wires, sheets and flowers. In this review, we use the basic concepts of supramolecular chemistry to discuss the molecular design strategy and growth mechanisms of various organic nano- and micro-structures, and their relationship with the corresponding applications. © The Royal Society of Chemistry 2011.


Yan X.,Max Planck Institute of Colloids and Interfaces | Su Y.,CAS Beijing National Laboratory for Molecular | Li J.,CAS Beijing National Laboratory for Molecular | Fruh J.,Max Planck Institute of Colloids and Interfaces | Mohwald H.,Max Planck Institute of Colloids and Interfaces
Angewandte Chemie - International Edition | Year: 2011

Riding the waves: An aldehyde triggers oriented long-range crystallization of self-assembling fibrous diphenylalanine peptide networks (see picture). The crystal growth is self-adjustable and likely subject to kinetic regulation, which leads to the 3D confinement of uniaxially oriented substructures in the resultant crystal. The peptide crystals exhibit remarkable thermal stability and optical waveguiding properties. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Garner D.K.,University of Illinois at Urbana - Champaign | Liang L.,CAS Beijing National Laboratory for Molecular | Barrios D.A.,University of Illinois at Urbana - Champaign | Zhang J.-L.,CAS Beijing National Laboratory for Molecular | Lu Y.,University of Illinois at Urbana - Champaign
ACS Catalysis | Year: 2011

Two questions important to the success in metalloenzyme design are how to attach or anchor metal cofactors inside protein scaffolds and in what way such positioning affects enzymatic properties. We have previously reported a dual anchoring method to position a nonnative cofactor, MnSalen (1), inside the heme cavity of apo sperm whale myoglobin (Mb) and showed that the dual anchoring can increase both the activity and enantioselectivity over single anchoring methods, making this artificial enzyme an ideal system to address the above questions. Here, we report systematic investigations of the effect of different covalent attachment or anchoring positions on reactivity and selectivity of sulfoxidation by the MnSalen-containing Mb enzymes. We have found that changing the left anchor from Y103C to T39C has an almost identical effect of increasing rate by 1.8-fold and increasing selectivity by +15% for S, whether the right anchor is L72C or S108C. At the same time, regardless of the identity of the left anchor, changing the right anchor from S108C to L72C increases the rate by 4-fold and selectivity by +66%. The right anchor site was observed to have a greater influence than the left anchor site on the reactivity and selectivity in sulfoxidation of a wide scope of other ortho-, meta- and para-substituted substrates. The 1 ·Mb(T39C/L72C) showed the highest reactivity (TON up to 2.32 min-1) and selectivity (ee % up to 83%) among the different anchoring positions examined. Molecular dynamic simulations indicate that these changes in reactivity and selectivity may be due to the steric effects of the linker arms inside the protein cavity. These results indicate that small differences in the anchor positions can result in significant changes in reactivity and enantioselectivity, probably through steric interactions with substrates when they enter the substrate-binding pocket, and that the effects of right and left anchor positions are independent and additive in nature. The finding that the anchoring arms can influence both the positioning of the cofactor and steric control of substrate entrance will help design better functional metalloenzymes with predicted catalytic activity and selectivity. © 2011 American Chemical Society.


Shen Y.,CAS Beijing National Laboratory for Molecular | Shen Y.,University of Chinese Academy of Sciences | Chen C.-F.,CAS Beijing National Laboratory for Molecular
Chemical Reviews | Year: 2012

Work done in the field of helicenes from 1900s to the early 2011 is reviewed. In 1967, Martin and co-workers reported the first photoinduced synthesis of heptahelicene. Katz et al. developed another impressive strategy using excess propylene oxide plus a stoichiometric amount of iodine in an inert atmosphere, which not only enhances the yields greatly compared with the traditional conditions for the photocyclization of stilbenes but also prevents photoreduction or photooxidative side reactions of the double bonds. A Ru-catalyzed double cyclization through a naphthoannulation procedure based on 1,1-diaryl-2,2-diethynylethylenes, was disclosed by Scott and Donovan in 2004. Hassine and coworkers utilized β-styrylpyridine as one aryl moiety to give two helicene isomers after Mizoroki-Heck coupling and a photocyclization. Staab and co-workers reported the use of Stille-Kelly coupling to synthesize 1,16-diaza[6]helicene in 52% yield in the presence of hexamethyldistannane.


Li Z.,CAS Beijing National Laboratory for Molecular | Liu W.,CAS Beijing National Laboratory for Molecular
Journal of Chemical Physics | Year: 2010

The spin-adaptation of single-reference quantum chemical methods for excited states of open-shell systems has been nontrivial. The primary reason is that the configuration space, generated by a truncated rank of excitations from only one component of a reference multiplet, is spin-incomplete. Those "missing" configurations are of higher ranks and can, in principle, be recaptured by a particular class of excitation operators. However, the resulting formalisms are then quite involved and there are situations [e.g., time-dependent density functional theory (TD-DFT) under the adiabatic approximation] that prevent one from doing so. To solve this issue, we propose here a tensor-coupling scheme that invokes all the components of a reference multiplet (i.e., a tensor reference) rather than increases the excitation ranks. A minimal spin-adapted n -tuply excited configuration space can readily be constructed by tensor products between the n -tuple tensor excitation operators and the chosen tensor reference. Further combined with the tensor equation-of-motion formalism, very compact expressions for excitation energies can be obtained. As a first application of this general idea, a spin-adapted open-shell random phase approximation is first developed. The so-called "translation rule" is then adopted to formulate a spin-adapted, restricted open-shell Kohn-Sham (ROKS)-based TD-DFT (ROKS-TD-DFT). Here, a particular symmetry structure has to be imposed on the exchange-correlation kernel. While the standard ROKS-TD-DFT can access only excited states due to singlet-coupled single excitations, i.e., only some of the singly excited states of the same spin (Si) as the reference, the new scheme can capture all the excited states of spin Si -1, Si, or Si +1 due to both singlet- and triplet-coupled single excitations. The actual implementation and computation are very much like the (spin-contaminated) unrestricted Kohn-Sham-based TD-DFT. It is also shown that spin-contaminated spin-flip configuration interaction approaches can easily be spin-adapted via the tensor-coupling scheme. © 2010 American Institute of Physics.


Zhang Z.,CAS Beijing National Laboratory for Molecular | Guo H.,CAS Beijing National Laboratory for Molecular
Journal of Chemical Physics | Year: 2010

We present a systematic dissipative particle dynamics (DPD) study on the phase behavior, structure, and dynamics of rodlike mesogens. In addition to a rigid fused-bead-chain model with RATTLE constraint method, we also construct a semirigid model in which the flexibility is controlled by the bending constant of kφ. Using this notation, the rigid model has an infinite bending constant of kφ =∞. Within the parameter space studied, both two kinds of models exhibit the nematic and smectic-A phases in addition to the isotropic and solid phases. All of the phase transitions are accompanied by the discontinuities in the thermodynamical, structural, and dynamical quantities and the hysteresis around the transition points, and are therefore first order. Note that the obtained solid state exhibits an in-layer tetragonal packing due to the high density. For the rigid model, the simulations show that the liquid crystal phases can be observed for mesogens with at least five beads and the nematic phase is the first one to appear. More importantly, the phase diagram of seven-bead-chain models is obtained as a function of k φ and temperature. It is found that decreasing the value of kφ reduces the anisotropy of molecular shape and the orientational ordering, and thereby shifts the liquid crystal phases to the lower temperature end of the phase diagram. Due to the different k φ dependence of phase transition temperatures, the nematic phase range exhibits a more marked narrowing than the smectic-A phase as k φ is reduced, implying that the flexibility has a destabilizing effect on the nematic and smectic-A phases. We also have investigated the anisotropic translational diffusion in liquid crystal phases and its temperature and flexibility dependence. In our study, we find that the phases formed, their statical and dynamic properties, as well as the transition properties are in close accord with those observations in real thermotropic liquid crystals. It is clear that both the rigid and semirigid models we used are valuable models with which to study the behavior of thermotropic liquid crystals using DPD algorithm. © 2010 American Institute of Physics.


Duan P.,CAS Beijing National Laboratory for Molecular | Liu M.,CAS Beijing National Laboratory for Molecular
Physical Chemistry Chemical Physics | Year: 2010

A series of dendrimers containing focal aromatic rings, ranged from phenyl, naphthyl, anthryl to pyrenyl, and the l-glutamate peripheral groups were designed and their self-assembly through the air/water interface was investigated. It has been found that although these dendrimers have no long alkyl chains, some of the dendrimers could form stable monolayers at the air/water interface due to an appropriate balance between the hydrophobic core and the hydrophilic peripheral group. Nanofibers were observed for the monolayers of the dendrimer containing a 2-anthryl group, while nanostrips were observed for that containing a pyrenyl group. In contrast to the dendrimers in solution, the molecular chirality at the chiral center of l-glutamate was transferred to the supramolecular assemblies in the films, indicating the effect of the interfacial assembly. For the dendrimers containing an anthryl core, photodimerization occurred. The photoirradiation was carried out under different conditions such as in solution, in a floating monolayer and in the transferred LB films. Different morphologies were obtained. These results indicated that the photoreaction of an anthryl dendrimer can be regulated through the interfacial organization, which leads to different packing as well as the subsequent photoreaction. © 2010 the Owner Societies.


Miao W.,Lingnan Normal University | Yang D.,CAS Beijing National Laboratory for Molecular | Liu M.,CAS Beijing National Laboratory for Molecular
Chemistry - A European Journal | Year: 2015

Abstract A new class of homologous gelators, LG12-(CH2)n-BSA, composed of bipyridinyl groups, L-glutamic moieties having double dodecyl chains, and linked alkyl spacers with different lengths were synthesized. It was found that these gelators could immobilize medium-polarity solvents readily and the behaviors of these gels showed a dependence on the spacer length. Of all the gels, the LG12-(CH2)11-BSA gels exhibited self-healing property and multiple-stimulus responsibility, such as heating, shaking, and sonication. The investigation of CD spectra indicated that the supramolecular chirality, which was attributed to the chiral transfer from the chiral center to the assemblies, was also closely related to the length of methylene spacers. The longer the alkyl spacers, the weaker the transmitted supramolecular chirality. Only LG12-(CH2)1-BSA gelators, which had the shortest spacers, formed right-handed nanoscale chiral twists owing to crowded hydrogen bonding interactions. Moreover, the high-polarity solvent DMF was found to be able to regulate the chiral twist as well as its pitch length readily. A new twist on healing: Self-healing supramolecular gels that are responsive to multiple stimuli were developed. The formation of nanoscale twists could be controlled by the length of the methylene spacers of the gelator molecules. The pitch of these twists could be regulated by DMF. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Mao N.,CAS National Center for Nanoscience and Technology | Mao N.,CAS Beijing National Laboratory for Molecular | Chen Y.,CAS National Center for Nanoscience and Technology | Liu D.,Tsinghua University | And 2 more authors.
Small | Year: 2013

The effect of surrounding solvents on the photoluminescence (PL) of MoS2 monolayers on Si/SiO2 substrates is studied. A redshift (up to -60 meV) is observed for MoS2 monolayers with nonhalogenated solvent surroundings. A blueshift (up to 60 meV) and intensity increase (2-50 times) are observed for monolayers with halogenated solvent surroundings. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zhang Z.,CAS Beijing National Laboratory for Molecular | Chen G.,CAS Beijing National Laboratory for Molecular | Wang H.,National Center for Nanosciences and Technology of China | Zhai W.,CAS Ningbo Institute of Material Technology and Engineering
Journal of Materials Chemistry C | Year: 2015

A new strategy, i.e. interfacial adsorption-soft template polymerization, is developed to enhance polymer thermoelectric property. The obtained nanocomposite 3D interconnected architecture consisting of reduced graphene oxide (rGO) nanolayers sandwiched by polypyrrole (PPy) nanowires is directly confirmed by scanning and transmission electron microscopies. Moreover, the nanocomposites reveal significantly enhanced thermoelectric performance. At rGO : PPy ratio of 50 wt%, the nanocomposite power factor reaches ∼476.1 times that of pure PPy nanowires. Our results suggest that a greatly enhanced thermoelectric property for polymer nanocomposites can be achieved by a complex morphology design. © 2015 The Royal Society of Chemistry.


Wang Y.,CAS Beijing National Laboratory for Molecular | Du H.,CAS Beijing National Laboratory for Molecular
Journal of Organic Chemistry | Year: 2010

This paper describes a copper(II) acetate-mediated cyclization- acetoxylation of 6,8-dien-1-ones in the presence of sodium acetate as base. A variety of functionalized cyclopentanes containing synthetic useful allylic alcohol moieties with three contiguous stereogenic centers were synthesized in moderate to good yields with moderate to high regioselectivities. © 2010 American Chemical Society.


Wang W.,Peking University | Zhao Q.,Peking University | Li H.,Peking University | Wu H.,CAS Beijing National Laboratory for Molecular | And 2 more authors.
Advanced Functional Materials | Year: 2012

Transparent, double-sided, flexible, ITO-free dye-sensitized solar cells (DSSCs) are fabricated in a simple, facile, and controllable way. Highly ordered, high-crystal-quality, high-density ZnO nanowire arrays are radially grown on stainless steel, Au, Ag, and Cu microwires, which serve as working electrodes. Pt wires serve as the counter electrodes. Two metal wires are encased in electrolyte between two poly(ethylene terephthalate) (PET) films (or polydimethylsiloxane (PDMS) films) to render the device both flexible and highly transparent. The effect of the dye thickness on the photovoltaic performance of the DSSCs as a function of dye-loading time is investigated systematically. Shorter dye-loading times lead to thinner dye layers and better device performance. A dye-loading time of 20 min results in the best device performance. An oxidation treatment of the metal wires is developed effectively to avoid the galvanic-battery effect found in the experiment, which is crucial for real applications of double-metal-wire DSSC configurations. The device shows very good transparency and can increase sunlight use efficiency through two-sided illumination. The double-wire DSSCs remain stable for a long period of time and can be bent at large angles, up to 107°, reversibly, without any loss of performance. The double-wire-PET, planar solar-cell configuration can be used as window stickers and can be readily realized for large-area-weave roll-to-roll processing. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Chen Q.,CAS Beijing National Laboratory for Molecular | Shen X.,CAS Beijing National Laboratory for Molecular
Crystal Growth and Design | Year: 2010

Mesoporous microspheres with a larger pore size (diameter of pore: ca. 35 nm, Barrett-Emmett-Teller (BET) surface area: 25.6 m2/g), the radial arrangement of irregular BaSO4 nanorods, were successfully synthesized by the radiolysis of an aqueous solution of K2S 2O8, Ba(NO3)2, and disodium ethylenediaminetetraacetate with an irradiation time of 1000 min (dose rate: 20 Gy/min) at room temperature. It was confirmed that the mesoporous microspheres with a larger pore size evolved from the mesoporous microspheres with a smaller pore size (diameter of pore: ca. 4 nm, BET surface area: 49.6 m2/g), which were generated at the early stage of the irradiation course and were mainly constructed by quasi-spherical nanoparticles, via Ostwald ripening at room temperature. © 2010 American Chemical Society.


Zheng Z.,University of Chinese Academy of Sciences | Kuang F.,CAS Beijing National Laboratory for Molecular | Zhao J.,CAS Beijing National Laboratory for Molecular
Macromolecules | Year: 2010

The defocus fluorescence microscopy method employed to study the segmental motion in polystyrene (PS) thin films has been reported. The excitation laser beam was introduced through an oil-immersion objective lens and wide-field fluorescence images were recorded at controlled timing. The analysis of images showed that most molecules (>95%) were oriented parallel to the substrate's surface, as demonstrated by the symmetrical dumbbell-shaped patterns in the defocus fluorescence images. The results showed that all of the molecules were immobilized under the temperature studied, and no translational diffusion was observed. The analysis of rotation rate was conducted, and the data showed very wide distributions, from one fluorophore to another, as well as from time to time for one specific fluorophore. The effect of photobleaching was studied that showed that the fR value for the 11.5 nm thick samples at 40° was ~2% and it increased extensively to 95% at 44°C.


Sun Y.,CAS Beijing National Laboratory for Molecular | Chen H.,CAS Beijing National Laboratory for Molecular
Journal of Chemical Theory and Computation | Year: 2013

Coupled cluster CCSD(T) calculations with core-valence correlation and complete basis set (CBS) limit extrapolation are used to benchmark the performance of commonly used density functionals in computing energy barriers for Zr-mediated reactions involving zirconocene species. These reactions include (a) insertions of the Zr-H bond of Cp2Zr(H)Cl into C=C, Cî - C, and C=O bonds and (b) C-H activations by Zr=N bond in Cp2Zr=NH. The best performing functionals are M06-L, M06, and M06-2X in the M06 series, all having mean unsigned deviations (MUD) less than 2 kcal/mol. The worst performing functional is OLYP, with a distinctly large MUD of more than 10 kcal/mol. Considering also the trends in barrier heights and the systematic barrier height deviation, our best recommended functional is M06-2X. In this work, DFT empirical dispersion correction (DFT-D3) is found to improve the performance of barrier height values for most functionals (especially of OLYP and B3LYP). With DFT empirical dispersion correction, we also recommend M06-2X for reaction barrier calculations of Zr-mediated reactions. © 2013 American Chemical Society.


Man X.,CAS Beijing National Laboratory for Molecular | Yan D.,CAS Beijing National Laboratory for Molecular
Macromolecules | Year: 2010

Self-consistent-field theory (SCFT) is presented to study the charge inversion phenomena by flexible polyelectrolytes (PE) adsorbed onto oppositely charged cylindric surfaces. We focus on the effect of surface curvature on the charge inversion ratio between the area density of surface charge compensated by the adsorbed polymers and the area density of origin surface charge. Numerical results show that surface curvature does have a strong effect on the charge inversion phenomena. Namely, it can lead to strong charge inversion at high salt concentrations with strong surface-PE short-range non-Coulombic interaction even in a good solvent. In particular, under large surface curvature and strong short-range non-Coulombic interaction conditions, full charge inversion can even happen at low salt concentrations. Moreover, numerical results show that the surface curvature has a different effect on the charge inversion ratio in the regime dominated by the surface-PE electrostatic interaction and in the regime dominated by the surface-PE shortrange non-Coulombic interaction. Increasing surface curvature will decrease the charge inversion ratio in the former case, while it will increase it in the latter case. Also, we numerically obtain a crossover point for the cylinder radius, which approximately equates to 2 times the gyration radius of PE chain. When the cylinder radius becomes larger than it, the surface curvature will lose its effect on the charge inversion. The numerical results give a further demonstration that, in these weakly charged systems, the surface-PE short-range nonCoulombic interaction is the main driving force of charge inversion phenomena. The results are in good agreement with the theoretical and experimental results. © 2010 American Chemical Society.


Yan Y.,CAS Beijing National Laboratory for Molecular | Zhao Y.S.,CAS Beijing National Laboratory for Molecular
Advanced Functional Materials | Year: 2012

Nanophotonic circuits meet exciton polaritons (EPs) in organic nanomaterials: Great possibilities for the use of organic 1D crystalline nanostructures as building blocks are emerging. These remarkable studies will contribute significantly to the development of EP-based on-chip photonic devices in the near future. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zhang J.,CAS Beijing National Laboratory for Molecular | Maurer F.H.J.,Lund University | Yang M.,CAS Beijing National Laboratory for Molecular
Journal of Physical Chemistry C | Year: 2011

TiO2 nanoparticles were in situ generated in one-dimensional poly(methyl methacrylate) PMMA nanohybrid fibers with excellent dispersion by using electrospinning combined with a sol-gel method followed by a mild hydrothermal treatment that preserves the properties of the polymer to the maximum degree. Detailed information of the preparation method, synthesis route, structure and properties of TiO2/PMMA nanohybrids is revealed. The possible rationale for the uniform formation of TiO2 nanoparticles in the PMMA matrix is discussed with respect to the role of the acid solvent trifluoroacetic acid (TFA) as well as the electrospun fiber structure in the sol-gel and hydrothermal process. The use of TFA in the preparation of electrospun precursor/PMMA solutions induces full hydrolysis of titanium alkoxide. The rapid electrospinning process suppresses the condensation reaction of the precursor. The strong hydrogen bonding interaction between hydrolyzed inorganic precursor and the polymer results in stable precursor/PMMA nanohybrids at ambient conditions. The solid fibrous polymer structure facilitates the generation and homogeneous distribution of nanosized TiO2 particles within the PMMA matrix at hot water conditions, which are ready to be used in biomedical and optical applications. © 2011 American Chemical Society.


Zhang C.,Tianjin University | Chen P.,Tianjin University | Chen P.,CAS Beijing National Laboratory for Molecular | Hu W.,Tianjin University | Hu W.,CAS Beijing National Laboratory for Molecular
Chemical Society Reviews | Year: 2015

Organic field-effect transistors (OFETs) are one of the key components of modern organic electronics. While the past several decades have witnessed huge successes in high-performance OFETs, their sophisticated functionalization with regard to the responses towards external stimulations has also aroused increasing attention and become an important field of general concern. This is promoted by the inherent merits of organic semiconductors, including considerable variety in molecular design, low cost, light weight, mechanical flexibility, and solution processability, as well as by the intrinsic advantages of OFETs including multiparameter accessibility and ease of large-scale manufacturing, which provide OFETs with great potential as portable yet reliable sensors offering high sensitivity, selectivity, and expeditious responses. With special emphases on the works achieved since 2009, this tutorial review focuses on OFET-based gas sensors. The working principles of this type of gas sensors are discussed in detail, the state-of-the-art protocols developed for high-performance gas sensing are highlighted, and the advanced gas discrimination systems in terms of sensory arrays of OFETs are also introduced. This tutorial review intends to provide readers with a deep understanding for the future design of high-quality OFET gas sensors for potential uses. © 2015 The Royal Society of Chemistry.


Zhang Y.,CAS Beijing National Laboratory for Molecular | Jiang H.,CAS Beijing National Laboratory for Molecular
Journal of Chemical Theory and Computation | Year: 2011

Accurate evaluation of the total energy difference between different spin states in molecular magnetic systems is currently a great challenge in theoretical chemistry. In this work we assess the performance of the density functional theory plus the Hubbard U (DFT+U) approach for the first-principles description of the high spin-low spin (HS-LS) splitting and the exchange coupling constant, corresponding to the intra- and interatomic spin interactions, respectively. The former is investigated using a set of mononuclear ion complexes with different HS-LS splitting, including seven spin-crossover (SCO) compounds, while the latter is investigated in a series of binuclear copper complexes covering both ferromagnetic and antiferromagnetic interactions. We find that the DFT+U approach can reproduce experimental data as accurately as the hybrid functionals approach but with much lower computational efforts. We further analyze the effect of U in terms of spin density on magnetic centers, and we find that the main effect of the U correction can be attributed to the enhanced localization of magnetic orbitals. Even taking the uncertainty related to the determination of U into account, we think the DFT+U approach is an efficient and predictive first-principles method for the SCO phenomenon and interatomic magnetic interactions. © 2011 American Chemical Society.


Zhang X.,Beijing Institute of Technology | Zhang X.,CAS Beijing National Laboratory for Molecular | Li Y.,Beijing Institute of Technology | Cao C.,Beijing Institute of Technology
Journal of Materials Chemistry | Year: 2012

Mesoporous silica/carbon nanomaterials with various hierarchical structures have been fabricated by a one-pot approach. Polymer/silica/surfactant (PSS) composites are first prepared by the co-sol-gel process of TEOS and resorcinol-formaldehyde precursor in the presence of CTAB. The PSS morphologies could be tuned by simply altering the content of ethanol in solution. © 2012 The Royal Society of Chemistry.


Qi B.,CAS Beijing National Laboratory for Molecular | Wang J.,CAS Beijing National Laboratory for Molecular
Journal of Materials Chemistry | Year: 2012

Open-circuit voltage (VOC) is the maximum voltage a solar cell can provide to an external circuit, which is derived from the splitting of hole and electron quasi-Fermi levels. In crystalline Si solar cells, the effective density of states at the bottom (top) of the conduction (valence) band is constant, and the quasi-Fermi level can be directly calculated via the Fermi-Dirac distribution. However, in organic materials, similar to amorphous Si, disorder induces gap tail states. Relaxation of carriers into these tail states brings the electron quasi-Fermi level down and the hole quasi-Fermi level up, and hence reduces VOC. Furthermore, carrier recombination of various kinds can cause additional loss of VOC. This article reviews the research progress in understanding the origin of VOC in organic solar cells. In particular, the dependence of VOC on four important factors, namely temperature, light intensity, work function of the electrode and material microstructure are discussed based on the model of density of states. Techniques to enhance VOC are also briefly introduced and their mechanisms are analysed. © The Royal Society of Chemistry 2012.


Li G.,CAS Beijing National Laboratory for Molecular | Mao L.,CAS Beijing National Laboratory for Molecular
RSC Advances | Year: 2012

A magnetically separable Fe3O4-Ag3PO 4 sub-micrometre composite was synthesized in large quantities by a fast and simple route, and was demonstrated to have a high photocatalytic efficiency toward the decomposition of methylene blue dye under visible light irradiation with a good recyclability. © 2012 The Royal Society of Chemistry.


Sun C.-L.,CAS Beijing National Laboratory for Molecular | Sun C.-L.,Chinese Academy of Sciences | Sun C.-L.,Nankai University | Shi Z.-J.,CAS Beijing National Laboratory for Molecular | And 2 more authors.
Chemical Reviews | Year: 2014

Recent advances on the transition-metal-free coupling reactions are reviewed. Electrophilic aromatic substitution was one of the earliest studied reactions, and the famous Friedel-Crafts reactions have been broadly studied and applied in organic synthesis, though they are not always mentioned while categorized as transition-metal-free coupling reactions. Similarly, nucleophilic aromatic substitution also represents typical transition-metal-free coupling reactions used for electron-deficient aromatic substrates. In radical pathway, base-promoted HAS reactions are a new kind of efficient intermolecular and intramolecular coupling reactions of aryl halides with aromatic compounds and unveil a new method to generate aryl radicals from aryl halides promoted by base-ligand complexes. Hyperiodine(III)-reagent-mediated oxidative couplings for C-C and C-N bond formation reactions are rather simple and clear alternatives to transition-metalcatalyzed editions, especially in the construction of nitrogen-containing heterocycles. In transition-metal-free coupling reactions, photoinduced conditions are usually greatly beneficial for electron transfer to generate active species, such as aryl radicals or aryl cations. Aryne chemistry is also introduced in transition-metal-free couplings of aryl halides for carbon-carbon and carbon-heteroatom bond formation. In transition-metal-catalyzed coupling reactions, the reactions can be modified by tuning many parameters, such as oxidative states of the center metals, ligands coordinated, counteranions.


Shuai Z.,Tsinghua University | Geng H.,CAS Beijing National Laboratory for Molecular | Xu W.,CAS Beijing National Laboratory for Molecular | Liao Y.,Capital Normal University | Andre J.-M.,Tsinghua University
Chemical Society Reviews | Year: 2014

This review introduces the development and application of a multiscale approach to assess the charge mobility for organic semiconductors, which combines quantum chemistry, Kinetic Monte Carlo (KMC), and molecular dynamics (MD) simulations. This approach is especially applicable in describing a large class of organic semiconductors with intermolecular electronic coupling (V) much less than intramolecular charge reorganization energy (λ), a situation where the band description fails obviously. The charge transport is modeled as successive charge hopping from one molecule to another. We highlight the quantum nuclear tunneling effect in the charge transfer, beyond the semiclassical Marcus theory. Such an effect is essential for interpreting the "paradoxical" experimental finding that optical measurement indicated "local charge" while electrical measurement indicated "bandlike". Coupled MD and KMC simulations demonstrated that the dynamic disorder caused by intermolecular vibration has negligible effect on the carrier mobility. We further apply the approach for molecular design of n-type materials and for rationalization of experimental results. The charge reorganization energy is analyzed through decomposition into internal coordinates relaxation, so that chemical structure contributions to the intramolecular electron-phonon interaction are revealed and give helpful indication to reduce the charge reorganization energy. This journal is © the Partner Organisations 2014.


Liu J.-W.,Lanzhou University | Yang Y.,CAS Beijing National Laboratory for Molecular | Chen C.-F.,CAS Beijing National Laboratory for Molecular | Ma J.-T.,Lanzhou University
Langmuir | Year: 2010

Two novel low-molecular-weight organogelators (LMOGs) 1 and 2 composed of an anthraquinone unit, a hydrazide group, and long alkyl chains were synthesized. They could form stable gels in wide tested solvents. Chloroalkanes and aromatic solvents tend, to result in transparent gels, while alcohol and other solvents yield opaque gels. The FT-IR, PXRD, and 1H NMR spectral studies revealed that hydrogen bonding and π-π interactions were the main driving forces for formation of the gels. Although the hydrazide unit and the anthraquinone group were connected by the σ-bond, the chloroform gel. of 1 could be changed into a red solution upon the addition of anion (F-, AcO-, and H2PO4 -) due to the disruption of the intermolecular hydrogen-bondings. Moreover, the red color clearly faded at once and the solution regelated upon the addition of methanol. The results indicated that 1 and 2 as smart anion-responsive gel might provide the basis for the development of nonfluid systems for sensing anion with the naked eye. © 2010 American Chemical Society.


Yao W.,CAS Beijing National Laboratory for Molecular | Zhao Y.S.,CAS Beijing National Laboratory for Molecular
Nanoscale | Year: 2014

Organic nanomaterials have attracted more and more attention for their applications in nano-photonics due to their high photoluminescence quantum efficiencies, color tunabilities, and size-dependent optical properties. With the distinctive features of photoluminescence, waveguiding and dimensional confinement, different organic nanostructures, such as 0D nanoparticles, 1D nanowires and 2D nanosheets, have a significant influence on their photonic properties. Therefore, it is of great importance and scientific interest to develop the strategy for tailoring the self-assembled structures with specific photonic behaviors in desired manners. In this mini review, we give a brief review of the recent work on the control of self-assembled organic nanostructures, and the tunable photonic properties of the predetermined structures. This journal is © the Partner Organisations 2014.


Gao X.,University of Science and Technology Beijing | Xu L.-P.,University of Science and Technology Beijing | Xue Z.,CAS Beijing National Laboratory for Molecular | Feng L.,Tsinghua University | And 4 more authors.
Advanced Materials | Year: 2014

Large-area dual-scaled porous nitrocellulose (p-NC) membranes are fabricated by a facile, inexpensive and scalable perforating approach. These p-NC membranes show stable superhydrophilicity in air and underwater superoleophobicity. The p-NC membranes with intrinsic nanopores and array of microscale perforated pores could selectively and efficiently separate water from various oil/water mixtures with high efficiency (> 99%) rapidly. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Li J.,CAS Beijing National Laboratory for Molecular | Xu D.,CAS Beijing National Laboratory for Molecular
Chemical Communications | Year: 2010

Tetragonal faceted-nanorods of single-crystalline anatase TiO2 with a large percentage of higher-energy {100} facets have been synthesized by hydrothermal transformation of alkali titanate nanotubes in basic solution. © 2010 The Royal Society of Chemistry.


Meng J.-H.,CAS Beijing National Laboratory for Molecular | Meng J.-H.,University of Chinese Academy of Sciences | He S.-G.,CAS Beijing National Laboratory for Molecular
Journal of Physical Chemistry Letters | Year: 2014

Laser-ablation-generated AuCeO2 + and CeO2 + oxide clusters were mass-selected using a quadrupole mass filter and reacted with H2 in an ion trap reactor at ambient conditions. The reactions were characterized by mass spectrometry and density functional theory calculations. The gold+cerium bimetallic oxide cluster AuCeO2 + is more reactive in H2 activation than the pure cerium oxide cluster CeO2 +. The gold atom is the active adsorption site and facilitates the heterolytic cleavage of H2 in collaboration with the separated O2- ion of the CeO2 support. To the best of our knowledge, this is the first example of thermal H2 activation by a closed-shell atomic cluster, which provides molecular-level insights into the single gold atom catalysis over metal oxide supports. (Chemical Equation Presented). © 2014 American Chemical Society.


Li X.,CAS Beijing National Laboratory for Molecular | Xi Z.,Nankai University | Luo S.,CAS Beijing National Laboratory for Molecular | Cheng J.-P.,Nankai University
Advanced Synthesis and Catalysis | Year: 2010

A highly enantioselective Michael addition of 3-substituted benzofuran-2(3H)-ones to chalcones catalyzed by a chiral bifunctional thiourea was developed. Several chiral 3,3′-substituted benzofuran-2(3H)-ones derivatives, bearing adjacent quaternary-tertiary stereocenters, were efficiently synthesized with excellent enantioselectivities. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.


Liu H.,CAS Beijing National Laboratory for Molecular | Du D.-M.,Beijing Institute of Technology | Du D.-M.,CAS Beijing National Laboratory for Molecular
Advanced Synthesis and Catalysis | Year: 2010

The new diphenylamine-linked bis(imidazoline) ligands were prepared through Kelly-You's imidazoline formation procedure mediated by Hendrickson 's reagent in good yields. The novel ligands were tested in the asymmetric Friedel-Crafts alkylation of indole derivatives with nitroalkenes. In most cases, good yields (up to 97%) and excellent enantioselectivities (up to 98%) can be achieved. The optimized bis(imidazoline) ligand with trans-diphenyl substitution on the imidazoline ring gave better enantioselectivity than the corresponding bis(oxazoline) ligand. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA,.


Deng T.,CAS Beijing National Laboratory for Molecular | Liu H.,CAS Beijing National Laboratory for Molecular
Journal of Molecular Catalysis A: Chemical | Year: 2014

The direct conversion of cellulose into acetol was studied on SnO x-modified Ni/Al2O3 catalysts with different Sn/Ni atomic ratios in the range of 0-2.0. The selectivity to acetol strongly depended on the Sn/Ni ratios, which reached the highest value of 53.9% at the ratio of 0.5, compared at similar cellulose conversions (∼20%). On Ni-SnOx/Al2O3 (Sn/Ni = 0.5), cellulose, glucose and fructose converted to acetol in high yields of approximately 35%, 53% and 73%, respectively, at 210 °C and 6 MPa H2. The effects of the Sn/Ni ratios on the acetol selectivity appear to be related to their effects on the hydrogenation activity of the Ni-SnOx/Al2O3 catalysts that decreased with increase of the Sn/Ni ratios, and to the relative rate between the hydrogenation of C6 sugar intermediates (e.g. glucose and fructose) and their degradation intermediates (e.g. glyceraldeyde and dihydroxyacetone) involved in the cellulose reaction on the Ni particles and the isomerization of glucose to fructose and their CC bond cleavage by retro-aldol condensation on the SnOx domains. Comparison of SnO x with CeOx, ZnOx and AlOx supported on Al2O3 with different basicity suggested that the larger concentration of stronger basic sites on SnOx facilitated the isomerizaiton of glucose to fructose and its subsequent CC bond cleavage. These results and their understanding provide guidance for improving the acetol production from cellulose by tuning the catalytic functions required for the involved reactions of hydrogenation on the metal surfaces, and isomerization and CC bond cleavage on the basic sites. © 2013 Elsevier B.V.


Yao A.,CAS Beijing National Laboratory for Molecular | Chu T.,CAS Beijing National Laboratory for Molecular
Dalton Transactions | Year: 2013

Imidazolium-based Fe-containing ionic liquids (ILs) can directly dissolve UO2 in the presence of their corresponding imidazolium chlorides without additional oxidants. The dissolution process follows pseudo first-order kinetics initially. Raman spectroscopic studies indicate that FeCl 4 2- is the predominant reduction product after UO 2 dissolution, and attenuated total reflection-Fourier transform infrared spectroscopy indicates that the UO2 2+ complex is the principal product in the ILs. The dissolved uranyl species can be successfully separated from the Fe-containing ILs via a combination of centrifugation and solvent extraction, and also, the Fe-containing ILs can be recovered easily. In conclusion, imidazolium-based Fe-containing ionic liquids in the presence of imidazolium chlorides could be used as effective and recoverable oxidants for the dissolution of UO2. © 2013 The Royal Society of Chemistry.


Hu S.-Z.,CAS Beijing National Laboratory for Molecular | Chen C.-F.,CAS Beijing National Laboratory for Molecular
Chemical Communications | Year: 2010

A triptycene-derived oxacalixarene with expanded cavity has been synthesized, and showed high efficient complexation abilities toward fullerenes C60 and C70. © 2010 The Royal Society of Chemistry.


Sun J.,CAS Beijing National Laboratory for Molecular | Liu H.,CAS Beijing National Laboratory for Molecular
Catalysis Today | Year: 2014

The selective hydrogenolysis of xylitol to ethylene glycol and propylene glycol was examined on Ni/C catalysts in the presence of solid bases, e.g. Ca(OH)2 and CeO2, physically mixed with or co-supported with Ni on C. Compared with Ru/C, the Ni/C catalysts were more selective to the two target glycols under identical conditions, apparently as a result of their lower hydrogenation activity and consequently favored the CC cleavage of xylose intermediate by the base catalyst over its competitive hydrogenation on the Ni particles. Noticeably, the presence of the solid bases rendered the Ni particles resistant to leaching and sintering, and thus stable in the xylitol hydrogenolysis. Supporting the solid bases, especially CeO2 and CaO, with the Ni particles on C led not only to a reduction in the amount of solid bases required, but also efficient formation of the two glycols with negligible lactic acid. For instance, on Ni-CaO/C (at a CaO/Ni molar ratio of 0.66), the combined selectivity to ethylene glycol and propylene glycol, together with glycerol, reached 69.5% at nearly 100% xylitol conversion at 473 K, 4.0 MPa H2. These features of the basic oxide-promoted Ni catalysts show their promising advantages over the noble Ru catalysts, upon optimization of their compositions and structures, and the reaction parameters, for the efficient hydrogenolysis of xylitol and other lignocellulose-derived polyols to produce the two target glycols. © 2014 Elsevier B.V.


Liu X.,CAS Beijing National Laboratory for Molecular | Liu X.,University of Chinese Academy of Sciences | Wang S.,CAS Beijing National Laboratory for Molecular
Chemical Society Reviews | Year: 2014

Three-dimensional nano-biointerface has been emerging as an important topic for chemistry, nanotechnology, and life sciences in recent years. Understanding the exchanges of materials, signals, and energy at biological interfaces has inspired and helped the serial design of three-dimensional nano-biointerfaces. The intimate interactions between cells and nanostructures bring many novel properties, making three-dimensional nano-biointerfaces a powerful platform to guide cell fate in a controllable and accurate way. These advantages and capabilities endow three-dimensional nano-biointerfaces with an indispensable role in developing advanced biological science and technology. This tutorial review is mainly focused on the recent progress of three-dimensional nano-biointerfaces and highlights the new explorations and unique phenomena of three-dimensional nano-biointerfaces for cell-related fundamental studies and biomedical applications. Some basic bio-inspired principles for the design and creation of three-dimensional nano-biointerfaces are also delivered in this review. Current and further challenges of three-dimensional nano-biointerfaces are finally addressed and proposed. This journal is © the Partner Organisations 2014.


Hu Z.,CAS Beijing National Laboratory for Molecular | Chen G.,CAS Beijing National Laboratory for Molecular
Journal of Materials Chemistry A | Year: 2014

Water was used to replace the toxic organic solvent of formamide in preparation of the aqueous dispersions of layered double hydroxide/ polyacrylamide (LDH/PAM) nanocomposites, which exhibited greatly enhanced rheological properties when compared to those of the neat PAM. First, the nanocomposite dispersions were prepared via a convenient in situ polymerization or solution mixing method, using water to exfoliate the LDH particles instead of formamide as used in the pioneer investigation. The LDH dispersion structure in the nanocomposite dispersion was demonstrated by X-ray diffraction and direct observation. Then, the rheological investigations including sol → gel transition, dynamic oscillatory frequency sweep and steady shear measurements were carried out. Subsequently, the rheological properties for the aqueous nanocomposite dispersions prepared by the two methods were compared. Finally, the mechanism of the enhancement of rheological properties (the moduli and viscosities) was discussed based on the LDH dispersion microstructure, network formation as well as interfacial interactions between PAM chains and LDH nanoparticles. This journal is © the Partner Organisations 2014.


Liu K.,Beihang University | Tian Y.,CAS Beijing National Laboratory for Molecular | Jiang L.,CAS Beijing National Laboratory for Molecular
Progress in Materials Science | Year: 2012

Through evolution, nature has arrived at what is optimal. Inspired by the biomaterials with special wettability, superhydrophobic materials have been well-investigated and -covered by several excellent reviews. The construction of superoleophobicity is more difficult than that of superhydrophobicity because the surface tension of oil or other organic liquids is lower than that of water. However, superoleophobic surfaces have drawn a great deal of attention for both fundamental research and practical applications in a variety of fields. In this contribution, we focus on recent research progress in the design, fabrication, and application of bio-inspired superoleophobic and smart surfaces, including superoleophobic-superhydrophobic surfaces, oleophobic-hydrophilic surfaces, underwater superoleophobic surfaces, and smart surfaces. Although the research of bio-inspired superoleophobicity is in its infancy, it is a rapidly growing and enormously promising field. The remaining challenges and future outlook of this field are also addressed. Multifunctional integration is a inherent characteristic for biological materials. Learning from nature has long been a source of bio-inspiration for scientists and engineers. Therefore, further cross-disciplinary cooperation is essential for the construction of multifunctional advanced superoleophobic surfaces through learning the optimized biological solutions from nature. We hope this review will provide some inspirations to the researchers in the field of material science, chemistry, physics, biology, and engineering. © 2012 Elsevier Ltd. All rights reserved.


Su J.,CAS Beijing National Laboratory for Molecular | Guo H.,CAS Beijing National Laboratory for Molecular
Journal of Physical Chemistry B | Year: 2012

From the perspectives of biological applications and material sciences, it is essential to understand the transport properties of water molecules through nanochannels. Although considerable effort and progress has been made in recent years, a systematic understanding of the effect of nanochannel dimension is still lacking. In this paper, we use molecular dynamics (MD) simulations to study the transport of water molecules through carbon nanotubes (CNTs) with various dimensions under pressure differences. We find an exponential decay describing the relation of the water flow and CNT lengths (L) for different pressures. The average translocation time of individual water molecules yields to a power law relation with L. We also exploit these results by comparing with the single-file transport, where some interesting relations were figured. Meanwhile, for a given CNT length, the water flow vs CNT diameters (R) can be depicted by a power law, which is found to be relevant to the water occupancy inside the nanochannel. In addition, we compare our MD results with predictions from the no-slip Hagen-Poisseuille (HP) relation. The dependence of the enhancement of the simulated water flux over the HP prediction on the CNT length and diameter supports previous MD and experimental studies. Actually, the effect of nanotube dimension is not only originated from the motion of water molecules inside the CNT but also related to thermal fluctuations in the bulk water outside the CNT. These results enrich our knowledge about the channel size effect on the water transportation, which should have deep implications for the design of nanofluidic devices. © 2012 American Chemical Society.


Li P.-F.,CAS Beijing National Laboratory for Molecular | Li P.-F.,University of Chinese Academy of Sciences | Chen C.-F.,CAS Beijing National Laboratory for Molecular
Chemical Communications | Year: 2011

A class of novel triptycene-derived calix[6]resorcinarene-like hosts have been designed and synthesized, and they are all cis-isomers with fixed cone conformation and can form head-to-head dimeric structures in the solid state. © The Royal Society of Chemistry 2011.


Yang S.,CAS Hefei Key Laboratory of Novel Thin Film Solar Cells | Wu X.,CAS Hefei Key Laboratory of Novel Thin Film Solar Cells | Chen C.,CAS Hefei Key Laboratory of Novel Thin Film Solar Cells | Dong H.,CAS Beijing National Laboratory for Molecular | And 2 more authors.
Chemical Communications | Year: 2012

This work reports a new graphene-based composite for supercapacitor material, and the maximum specific capacitance of 1760.72 F g -1 at a scan rate of 5 mV s -1, with excellent cycling stability. This journal is © The Royal Society of Chemistry 2012.


Wei S.,CAS Beijing National Laboratory for Molecular | Du H.,CAS Beijing National Laboratory for Molecular
Journal of the American Chemical Society | Year: 2014

Using a simple combination of tri-tert-butylphosphine and chiral borane generated in situ by the hydroboration of chiral diene with HB(C 6F5)2 as a frustrated Lewis pair catalyst, a highly enantioselective metal-free hydrogenation of silyl enol ethers was successfully realized to furnish a variety of optically active secondary alcohols in 93-99% yields with 88->99% ees. © 2014 American Chemical Society.


Wang H.,CAS Technical Institute of Physics and Chemistry | Wang H.,University of Chinese Academy of Sciences | Xie L.,Beijing University of Chemical Technology | Peng Q.,CAS Beijing National Laboratory for Molecular | And 5 more authors.
Advanced Materials | Year: 2014

Thermally activated delayed fluorescence emitters with small energy gap between the triplet and singlet (ΔEST), TXO-PhCz and TXO-TPA, have been successfully synthesized by combining a hole-transporting TPA/PhCz moiety and an electron-transporting TXO moiety. Both compounds display efficient solid-state luminescence with an efficient up-conversion of the triplet to singlet. OLEDs based on them exhibt high performance up to 21.5%, which is among the best reported for OLEDs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Yin Z.,Tianjin Polytechnic University | Lin L.,CAS Beijing National Laboratory for Molecular | Ma D.,CAS Beijing National Laboratory for Molecular
Catalysis Science and Technology | Year: 2014

Nanostructured Pd-based electrocatalysts have a large impact on cost, performance, and durability in the development of fuel cells. This review article provides an overview of recent advances in Pd-based electrocatalysts with a well-defined structure that can be applied for alcohol oxidation and oxygen reduction in an alkaline medium in direct alcohol fuel cells. These Pd-based catalytic materials include Pd electrocatalysts with different morphologies, monodisperse bimetallic Pd-based nanoparticles with different compositions and Pd-based nanoparticles with a well-controlled shape. Emphasis is placed on the atomic-level design of the nanoparticles' structure, and the origin of their electrochemical activity. The ways to enhance the electrocatalytic performance and design principles for Pd-based catalysts are discussed. This will help to shed light on the future development of non-Pt catalysts for fuel cells and accelerate the commercialization of fuel cell technology. © 2014 the Partner Organisations.


Pan F.,CAS Beijing National Laboratory for Molecular | Shi Z.-J.,CAS Beijing National Laboratory for Molecular | Shi Z.-J.,Chinese Academy of Sciences
ACS Catalysis | Year: 2014

Carbon-sulfur bonds widely exist in natural products, pesticides, and drugs, and their activation, cleavage, and transformation via transition metal catalysis have become more and more important in organic chemistry. During the past several decades, great progress on transition-metal catalyzed carbon-sulfur activation of thioesters and their transformations has been achieved. Carbon-sulfur bonds linking to both heteroaryl and aryl groups can be cleaved to construct carbon-carbon bonds by coupling reactions or to construct carbon-hydrogen bonds by reductions. This perspective is focused on recent advances in cleavage and transformations of transition-metal-catalyzed carbon-sulfur bonds. © 2013 American Chemical Society.


Zhi J.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Zhao W.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Liu X.,CAS Beijing National Laboratory for Molecular | Chen A.,CAS Hefei Key Laboratory of Materials for Energy Conversion | And 3 more authors.
Advanced Functional Materials | Year: 2014

Ordered mesoporous carbon (OMC) is considered one of the most promising materials for electric double layer capacitors (EDLC) given its low-cost, high specific surface area, and easily accessed ordered pore channels. However, pristine OMC electrode suffers from poor electrical conductivity and mechanical flexibility, whose specific capacitance and cycling stability is unsatisfactory in flexible devices. In this work, OMC is coated on the surface of highly conductive three-dimensional graphene foam, serving as both charge collector and flexible substrate. Upon further decoration with silver nanowires (Ag NWs), the novel architecture of Ag NWs/3D-graphene foam/OMC (Ag-GF-OMC) exhibits exceptional electrical conductivity (up to 762 S cm-1) and mechanical robustness. The Ag-GF-OMC electrodes in flexible supercapacitors reach a specific capacitance as high as 213 F g-1, a value five-fold higher than that of the pristine OMC electrode. Moreover, these flexible electrodes also exhibit excellent long-term stability with >90% capacitance retention over 10 000 cycles, as well as high energy and power density (4.5 Wh kg -1 and 5040 W kg-1, respectively). This study provides a new procedure to enhance the device performance of OMC based supercapacitors, which is a promising candidate for the application of flexible energy storage devices. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Dong H.,CAS Beijing National Laboratory for Molecular | Bo Z.,Beijing Normal University | Hu W.,CAS Beijing National Laboratory for Molecular
Macromolecular Rapid Communications | Year: 2011

A planar conjugated copolymer named HXS-1 was applied in thin film phototransistors. Similar to organic field-effect transistors using V G to control the source-drain current, in phototransistors, the light is used to substitute V G as an independent variable to control the output of the transistors to realize light detection and signal magnification in a single organic device. All devices exhibited high performance with an on/off ratio up to 4.6×10 4 (the highest on/off ratio of organic or polymer phototransistors), which could be assigned to i) the wide absorption features of HXS-1 in the whole UV-vis range, ii) the ideal HOMO energy level of HXS-1 (5.21 eV) to align with Au electrodes (5.2 eV) and iii) the high mobility of the polymer thin films (∼0.06 cm 2/Vs). Moreover, the devices, both under continuous operation conditions and long term measurement conditions, exhibited excellent stability, indicating potential applications of the devices in polymer-based optoelectronics. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Yu Y.,CAS Beijing National Laboratory for Molecular | Ma Y.,CAS Beijing National Laboratory for Molecular
Soft Matter | Year: 2011

Honeycomb films fabricated with small molecules via the breath figure (BF) method are reported. Water droplet templates were stabilized by self-assembled supramolecular architectures and a subsequent gelation process. The formed honeycomb film features a hydrogen bonded network of a dynamic nature. © 2011 The Royal Society of Chemistry.


Shi J.,CAS Beijing National Laboratory for Molecular | Shen X.,CAS Beijing National Laboratory for Molecular
Journal of Physical Chemistry B | Year: 2014

A new kind of biamphiphilic ionic liquid (BAIL) consisting of 1-dodecyl-3-methylimidazolium (C12mim+) and dodecyl sulfonate (DSN-) has been synthesized and characterized for the investigation on its self-assembling behavior with β-CD in the aqueous medium. Vesicles were found in the diluted C12mimDSN@3β-CD solution, and on increasing the concentrations of both IL and β-CD, the solution turned into a white hydrogel, which showed a temperature-dependent sol-gel transition. The building block consisting of one C12mimDSN and three β-CDs was proposed, and a novel self-assembly mechanism was studied. Both cation and anion of the BAIL are involved in the self-assembling with β-CD. The electronic interaction between C12mim+ and DSN-, the hydrophobic interaction between the alkyl chains of BAIL and β-CD cavity, H-bond between neighboring β-CDs, and the interaction between imidazolium headgroup and water in the hydrogel are the driving force for the self-assembly. © 2014 American Chemical Society.


Wang S.,CAS Beijing National Laboratory for Molecular | Sun W.-H.,CAS Beijing National Laboratory for Molecular | Redshaw C.,University of Hull
Journal of Organometallic Chemistry | Year: 2014

Recent progress on nickel-based complex pre-catalysts is reviewed herein. The ethylene oligo-/polymerization behaviour is discussed in terms of the variation of the complex models bearing different kinds of ligand sets. These discussions focus mainly on the influence that the different substituents present have on the observed catalytic activity, the results of which can guide the design of new target structures possessing high ethylene activity. © 2013 Elsevier B.V. All rights reserved.


Liao W.,CAS Beijing National Laboratory for Molecular | Yu Z.-X.,CAS Beijing National Laboratory for Molecular
Journal of Organic Chemistry | Year: 2014

Diels-Alder reaction between electronically neutral dienes and dienophiles is usually sluggish under thermal conditions and has to be catalyzed by transition metal catalysts. We report here our DFT study of the mechanism and stereochemistry of the Rh-catalyzed Diels-Alder reaction between electronically neutral dienes and dienophiles (alkenes and alkynes), finding that this reaction includes a reaction sequence of oxidative cyclization between diene and alkene/alkyne and a reductive elimination step. The alkyne's oxidative cyclization is much faster than alkene's due to the additional coordination of alkyne to the Rh center in the oxidative cyclization transition state. For both intermolecular and intramolecular reactions, the reductive elimination step in the catalytic cycle is rate-determining. The different reactivity of ene-diene and yne-diene substrates can be rationalized by the model that reductive elimination to form a C(sp2-C(sp3) bond is easier than that for the formation of a C(sp3)-C(sp3) bond, due to the additional coordination of the double bond to the Rh center in the transition state in the former. We also uncovered the reasons for the high para-selectivity of the intermolecular Diels-Alder reaction of dienes and alkynes. In addition, DFT calculations aiming to understand the high diastereoselectivity of an intramolecular [4 + 2] reaction of ene-dienes with substituents adjacent to the diene and ene moieties of the substrates found that the substituents in the substrates favor staying away from the Rh center in the oxidative cyclization transition states. This preference leads to the generation of the final [4 + 2] products with the substituents and the bridgehead hydrogen atoms in a cis-configuration. (Chemical Equation Presented). © 2014 American Chemical Society.


Zhu X.,CAS Beijing National Laboratory for Molecular | Du H.,CAS Beijing National Laboratory for Molecular
Organic and Biomolecular Chemistry | Year: 2015

An enantioselectiveusing a chiral borane catalyst generated by the in situ hydroboration of a binaphthyl-based chiral diene with Piers' borane HB(C6F5)2 to furnish a variety of optically active amines in 70% to >99% yields and 44-82% ees. This journal is © The Royal Society of Chemistry.


Zhu Q.,Shandong University | Han C.C.,CAS Beijing National Laboratory for Molecular
Polymer | Year: 2010

Well architectured polyurethanes containing fluorine are expected to be applied in medical devices as well as other fields. A telechelic polyurethane end-capped with perfluoropolyether segments was prepared from polyether glycol as a soft segment, 4, 4′-methylene-bis-(phenylisocyanate), and monofunctional perfluorinated oligomer. The telechelic polyurethane was studied by Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), contact angle and atomic force microscopy (AFM). XPS results indicated that the surface of the fluorine containing polyurethane was enriched with fluorine component. It exhibited a hydrophobic property with a water contact angle of 113°. The polyurethane terminated with perfluoropolyether segments showed a better thermal stability. A mechanism was proposed to explain thermal decomposition of polyurethanes. DSC results suggested that the tail-like perfluoropolyether segments would disrupt main chain packing, then raise crystallization potential barrier, and the perfluoropolyether segments did not affect the bulk microphase-separated structure. © 2010 Elsevier Ltd. All rights reserved.


Nie J.,CAS Beijing National Laboratory for Molecular | Liu H.,CAS Beijing National Laboratory for Molecular
Journal of Catalysis | Year: 2014

A cryptomelane-type manganese oxide octahedral molecular sieve with a (2 × 2, 4.6 Å × 4.6 Å) tunnel size (OMS-2) efficiently catalyzed aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) with a high yield of 97.2% at 383 K and 0.5 MPa O 2 in N,N-dimethylformamide. OMS-2 was superior to other MnO 2 catalysts with different morphologies, including OMS-1, OMS-6, and OMS-7 with various tunnel sizes, amorphous MnO2 and birnessite-type MnO2, apparently due to its (2 × 2) tunnel structure and consequently high reducibility and oxidizability. Kinetic and isotopic studies on OMS-2 showed near half-order dependence of the activities on HMF and O 2 concentrations and marked kinetic isotope effects for deuterated HMF at its methylene group. These results, together with the similar initial rates under aerobic and anaerobic conditions, suggest that HMF oxidation to DFF on OMS-2 proceeds via a redox mechanism involving kinetically-relevant steps of C-H bond cleavage in adsorbed alcoholate intermediate, derived from quasi-equilibrated dissociation of HMF, using lattice oxygen and reoxidation of Mn3+ to Mn4+ by dissociative chemisorption of O 2. © 2014 Elsevier Inc. All rights reserved.


Cao M.,Beihang University | Ju J.,CAS Beijing National Laboratory for Molecular | Li K.,CAS Beijing National Laboratory for Molecular | Dou S.,University of Wollongong | And 2 more authors.
Advanced Functional Materials | Year: 2014

Although clean drinking water is a basic human need, freshwater scarcity has been identified as a major global problem of the 21st century. Nature has long served as a source of inspiration for human beings to develop new technology. The cactus in the desert possesses a multifunctional integrated fog collection system originating from the cooperation of a Laplace pressure gradient and the wettability difference. In this contribution, inspired by the cactus, an artificial fog collector on a large scale is first fabricated through integrating cactus spine-like hydrophobic conical micro-tip arrays with the hydrophilic cotton matrix. The novel cactus-inspired fog collector can spontaneously and continuously collect, transport, and preserve fog water, demonstrating high fog collection efficiency and promising applications in the regions with drinking water scarcity. Furthermore, the present approach is simple, time-saving and cost-effective, which provides a potential device and new idea to solve the global water crisis. Inspired by the fog-harvesting behavior of the cactus, a novel fog collector in large scale is first fabricated through integrating cactus spine-like hydrophobic conical micro-tip arrays with a hydrophilic cotton matrix, which can spontaneously and continuously collect, transport, and preserve fog water. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Li M.,CAS Beijing National Laboratory for Molecular | Feng L.-H.,CAS Institute of Chemistry | Lu H.-Y.,University of Chinese Academy of Sciences | Wang S.,CAS Institute of Chemistry | Chen C.-F.,CAS Beijing National Laboratory for Molecular
Advanced Functional Materials | Year: 2014

Four new fluorescent dyes containing tetrahydro[5]helicene moiety characterized by three-primary emission colors (blue-green-red) are designed and synthesized, and their structures are characterized by NMR, MS, and single crystal X-ray crystallography. Organic nanoparticles based on the fluorescent dyes are then prepared by re-precipitation method, and their photophysical properties are investigated. These nanoparticles retain the strong emissions of the organic dyes, and multicolor nanoparticles were also prepared by simply tuning the ratios of the three-primary colors dyes. These organic nanoparticles exhibit low cytotoxicity, good photostability, and high quantum yields. Moreover, the nanoparticles can also be applied in the cell fluorescence imaging. Especially, it is interestingly found that the stained regions of these nanoparticles from membrane to cytoplasm for HeLa cells show obvious structure-dependent properties. This strategy provides a new perspective to fluorescence probe by molecular design for specific location imaging of living cells. A new kind of tetrahydro[5]helicene based fluorescent dyes with three-primary emission colors (blue-green-red) are synthesized, and the multicolor organic nanoparticles are then prepared. The nanoparticles exhibit low cytotoxicity, excellent photostability, and high quantum yields. Interestingly, the stained regions of these nanoparticles from membrane to cytoplasm for HeLa cells show obvious structure-dependent properties. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Wang T.,CAS Beijing National Laboratory for Molecular | Wang C.,CAS Beijing National Laboratory for Molecular
Accounts of Chemical Research | Year: 2014

Fullerenes are carbon cages assembled from fused hexagons andpentagons that have closed networks and conjugated π systems. The curve of the fullerene structure requires that the constituent carbon atoms take on a pyramidal shape and produces extra strain energy. However, the highly symmetrical geometry of the fullerene decreases the surface tension in these structures, so highly symmetrical fullerenes are usually very stable. For example, C60 with icosahedral symmetry (Ih) is the most stable fullerene molecule. However, another highly symmetrical fullerene, Ih-C80, is extremely unstable. The reason for this difference is the open-shell electronic structure of Ih-C80, which has a 4-fold degenerate HOMO occupied by only two electrons. Predictably, once the degenerate HOMO of I h-C80 accepts six more electrons, it forms a closed-shell electronic structure similar to Ih-C60 and with comparable stability. Because the hollow structure of fullerenes can encapsulate metal atoms and those internal metals can transfer electrons to the fullerene cage, the encapsulation of metal clusters may provide an ideal technique for the stabilization of the Ih-C80 fullerenes.In this Account, we focus on the molecular structures and paramagnetic properties of spherical Ih-C80 endohedral fullerenes encaging a variety of metal moieties, such as metal atoms (Mn), metal nitride (M3N), metal carbide (MnC2), metal carbonitride (M 3CN), and metal oxides (M4Om). We introduce several types of endohedral metallofullerenes such as Sc4C 2@Ih-C80, which exhibits a Russian-doll-like structure, and Sc3CN@Ih-C80, which encapsulates a planar metal carbonitride cluster. In addition, we emphasize the paramagnetic properties of Ih-C80-based metallofullerenes, such as Sc3C2@Ih-C80, Y2@C 79N, and M3N@Ih-C80, to show how those spin-active species can present a controllable paramagnetism. This Account highlights an inspiring molecular world within the spherical I h-C80 cages of various metallofullerenes. © 2013 American Chemical Society.


Chen X.-Y.,CAS Beijing National Laboratory for Molecular | Ye S.,CAS Beijing National Laboratory for Molecular
European Journal of Organic Chemistry | Year: 2012

Cyclic ketimines were successfully used as electrophiles in phosphane-catalyzed [4+2] annulation reactions with ethyl 2-methyl-2,3- butadienoate to give the corresponding highly substituted tetrahydropyridine derivatives in moderate to good yields (55-73 %), and with moderate to excellent regioselectivity. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zhang J.,CAS Beijing National Laboratory for Molecular | Yang M.,CAS Beijing National Laboratory for Molecular | Maurer F.H.J.,Lund University
Macromolecules | Year: 2011

Positron annihilation lifetime spectroscopy (PALS) has been performed on a series of PMMA nanohybrids containing nanometric TiO2, which were produced by means of different preparation methods, i.e., melt mixing, electrospinning combined with solution mixing, or in-situ sol-gel growth methods, to study the effect of filler content and constituents on the free volume properties. The PMMA nanocomposites containing titania precursor or in-situ-formed TiO2 additives exhibit altered free volume properties compared to adding commercial TiO2 P25 fillers. The orthopositronium (o-Ps) lifetime (τ3) (free volume cavity size) was constant with composition in P25/PMMA nanohybrids due to the absence of interfacial interaction. However, in TiO2 precursor/PMMA composite fibers the free volume cavity size decreased substantially with hydroxyl group concentration and recovered after hydrothermal treatment. Additionally, a strong correlation between the glass transition temperature and the o-Ps lifetime in the nanohybrids was observed. These effects are caused by the hydrogen-bonding interaction between hydroxyl groups in the inorganic phase and carbonyl groups in the PMMA matrix, which concentration is dependent on the hydrothermal treatment, leading to differences in the packing of the polymer chains and a changed polymer segmental flexibility. The results also show a clear linear decrease in the o-Ps yield (I3) with increasing P25 content of the composites. A dominant inhibition effect was observed in the TiO2 precursor/PMMA systems, caused by inhibition of positronium formation by the hydroxyl group in the titania precursor. In addition to the pronounced negative deviations of the o-Ps intensity with the concentration of hydroxyl groups in in-situ TiO2/PMMA nanohybrid fibers, a stronger inhibition efficiency of hydroxyl groups was observed than in the precursor/PMMA nanocomposite fibers. © 2011 American Chemical Society.


Zhan C.,CAS Beijing National Laboratory for Molecular | Yao J.,CAS Beijing National Laboratory for Molecular
Chemistry of Materials | Year: 2016

The power conversion efficiencies (PCEs) of organic solar cells are lower than that of recently emerging perovskite solar cells. Can a PCE of >12% be achieved with single-junction organic solar cells? To achieve a high PCE, much effort has been focused on the design and synthesis of electron-donor materials, including polymers and small molecules, and on innovative solar cell device structures. In this perspective, we focus on a different approach - replacing traditional fullerene acceptors with nonfullerene organic acceptors. This method is an interesting and powerful alternative for achieving more efficient organic solar cells because the molecular structures of organic acceptors can be easily chemically modified and their optoelectronic properties and aggregation behaviors are tunable. However, the film morphology affects charge separation, transport and collection and must therefore be considered when improving the electrical performance of nonfullerene organic solar cells (NF-OSCs). Herein, we discuss molecular strategies for obtaining high-efficiency nonfullerene organic acceptors, with particular focus on small molecules. We also highlight the challenges and opportunities in this field, namely, selecting novel donor-acceptor combinations, enhancing the material absorptivity to capture more solar photons, controlling the donor-acceptor interface structure to improve the charge separation, and tailoring the π-π-stacking structures and orientations to enhance mobile carrier transport and collection. NF-OSCs that are more efficient than traditional fullerene-based organic solar cells should be obtained by tailoring the organic acceptor structure and developing appropriate film-processing techniques, because these approaches are expected to produce NF-OSCs with a higher open-circuit voltage than their fullerene counterparts and comparable short-circuit current densities and fill factors. © 2016 American Chemical Society.


Yang L.,CAS Beijing National Laboratory for Molecular | Fan Y.,Methodist Hospital Research Institute | Gao Y.Q.,CAS Beijing National Laboratory for Molecular
Journal of Physical Chemistry B | Year: 2011

The higher tendency for anions to accumulate at the salt aqueous solution/air interface than that of cations has been observed experimentally and theoretically, suggesting that the size and polarizability of the ions play essential roles in this effect. Here, we investigate the influence of the nonsymmetrical positive-vs-negative charge distribution in water molecules to the hydration and surface/bulk partition of the solvated positively and negatively charged particles by using molecular dynamics simulations with hypothetical ions to validate our theoretical models. The results indicate that positive and negative charges (called cations and anions, respectively, although they may not really exist in experiments) with all other properties identical are hydrated differently and that the anions are more likely to populate at the surface. The simulation on a combination series of cations and anions in aqueous solution shows significant variations on water dynamics, likely due to the specific cooperativity between oppositely charged ions. © 2011 American Chemical Society.


Saleh F.S.,Tokyo Institute of Technology | Mao L.,CAS Beijing National Laboratory for Molecular | Ohsaka T.,Tokyo Institute of Technology
Sensors and Actuators, B: Chemical | Year: 2011

A simple and new way to immobilize glucose dehydrogenase (GDH) enzyme onto nile blue (NB) covalently assembled on the surface of functionalized single-walled carbon nanotubes (f-SWCNTs) modified glassy carbon (GC) electrode (GDH/NB/f-SWCNTs/GC electrode) was described. The GDH/NB/f-SWCNTs/GC electrode possesses promising characteristics as glucose sensor; a wide linear dynamic range of 100-1700 μM, low detection limit of 0.3 μM, fast response time (1-2 s), high sensitivity (14 μA cm-2 mM-1), anti-interference ability and anti-fouling. Moreover, the performance of the GDH/NB/f-SWCNTs/GC bioanode was successfully tested in a glucose/O2 biofuel cell. The maximum power density delivered by the assembled glucose/O2 biofuel cell could reach 32.0 μW cm-2 at a cell voltage of 0.35 V with 40 mM glucose. The present procedure can be applied for preparing a potential platform to immobilize different enzymes for various bioelectrochemical applications. © 2010 Elsevier B.V. All rights reserved.


Li Q.,CAS Beijing National Laboratory for Molecular | Yu Z.-X.,CAS Beijing National Laboratory for Molecular
Angewandte Chemie - International Edition | Year: 2011

Easy and efficient: By applying the title transformation, two adjacent sp3 stereogenic centers, one of which is a quaternary carbon center, can be easily formed. This asymmetric reaction provides easy and efficient access to multifunctionalized tetrahydropyrrole, tetrahydrofuran, and cyclopentane compounds (see scheme; coe=cyclooctene, DME=1,2-dimethoxyethane, Tf=trifluoromethanesulfonyl). © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Chen X.-Y.,CAS Beijing National Laboratory for Molecular | Wen M.-W.,University of Chinese Academy of Sciences | Ye S.,CAS Beijing National Laboratory for Molecular | Wang Z.-X.,University of Chinese Academy of Sciences
Organic Letters | Year: 2011

An unusual DABCO-catalyzed formal [4 + 2] cycloaddition of ethyl allenoate, as a surrogate of a "1,2-dipole", with various arylidenoxindoles has been developed for the synthesis of dihydropyran-fused indoles. The DFT mechanistic study indicates that the cycloaddition takes place stepwise and the essential role of the catalyst is to raise the HOMO of allenoate.(Figure Presented) © 2011 American Chemical Society.


Shi W.,CAS Beijing National Laboratory for Molecular | Ma H.,CAS Beijing National Laboratory for Molecular
Chemical Communications | Year: 2012

Spectroscopic probes have been extensively investigated and used widely in many fields because of their powerful ability to improve analytical sensitivity, and to offer greater temporal and spatial resolution (in some cases a molecule event may be visualized by the naked eye). So far, different photophysical mechanisms, such as charge transfer, photo-induced electron transfer and fluorescent resonance energy transfer, have been employed to develop various spectroscopic probes with superior properties. However, these photophysical mechanisms depend on the energy levels of molecular orbitals, which are usually difficult to accurately determine. This would lead to the poor prediction of analytical performance of the designed probe. Instead, the change of π-conjugated systems induced by chemical reactions is often accompanied by a distinct alteration in spectroscopic signal, which is more predictable and is of high signal/background ratio. This mechanism can serve as an effective measure for developing excellent spectroscopic probes, but to our knowledge, has not been systematically summarized. In this feature article, we review the development of spectroscopic probes with changeable π-conjugated systems, which is catalogued according to the fluorochromes: fluorescein, rhodamine, spiropyran, squaraine, coumarin, cyanine, etc. Two main strategies for constructing these spectroscopic probes, including ring-closing reaction and nucleophilic addition reaction, are summarized, and the merits and limitations of the probes are discussed. © 2012 The Royal Society of Chemistry.


Wang T.,CAS Beijing National Laboratory for Molecular | Ye S.,CAS Beijing National Laboratory for Molecular
Organic and Biomolecular Chemistry | Year: 2011

The triphenylphosphine-catalyzed formal [3 + 2] cycloaddition of allenoates and trifluoromethylketones was realized to give the corresponding dihydrofurans in good yields with excellent γ-regioselectivities. Hydrogenation of the dihydrofurans gave 2,4,4-trisubstituted tetrahydrofurans in good yields with exclusive cis-selectivities. © The Royal Society of Chemistry 2011.


Zhao X.,Tianjin Normal University | Zhang Y.,CAS Beijing National Laboratory for Molecular | Wang J.,CAS Beijing National Laboratory for Molecular
Chemical Communications | Year: 2012

Copper-catalyzed reaction of diazo compounds generates copper carbene intermediates that undergo diverse transformations. In recent years, the selectivity and efficiency of these important conversions have been further improved. In particular, breakthroughs have been made in catalytic asymmetric polar X-H bond insertion reactions. Moreover, novel transformations based on copper carbene, namely copper-catalyzed cross-couplings of diazo compounds, have emerged as powerful methods for carbon-carbon bond formations. This feature article summarizes the most recent developments in this area. © The Royal Society of Chemistry 2012.


Huang J.-H.,CAS Beijing National Laboratory for Molecular | Huang J.-H.,University of Chinese Academy of Sciences | Yang L.-M.,CAS Beijing National Laboratory for Molecular
Organic Letters | Year: 2011

The amination of triaryl phosphates was achieved using a Ni(II)-(σ-Aryl) complex/NHC catalyst system in dioxane at 110 °C in the presence of NaH as base. Electron-neutral, -rich, and -deficient triaryl phosphates were coupled with a wider range of amine partners including cyclic and acyclic secondary amines, aliphatic primary amines, and anilines in good to excellent yields. © 2011 American Chemical Society.


Ye X.,CAS Beijing National Laboratory for Molecular | Qi L.,CAS Beijing National Laboratory for Molecular
Nano Today | Year: 2011

Colloidal lithography based on monolayer colloidal crystals (MCCs) is a facile, inexpensive, efficient, and flexible nanofabrication approaches towards a wide variety of two-dimensionally (2D) patterned nanostructures with high controllability and reproducibility. This review gives a systematic overview on the recent advances in the controllable fabrication and assembly of 2D patterned nanostructures assisted by MCCs, with particular attention paid to the applications of the MCC-based nanostructures. First, the representative methods for the self-assembly of hexagonal-close-packed (hcp) MCCs and other complex MCCs are introduced. Next, the MCC-assisted fabrication (e.g., etching and deposition) of 2D patterned nanostructures at different two-phase (e.g., gas/solid, liquid/solid, and gas/liquid) interfaces is described, which is followed by a discussion on the MCC-assisted assembly from preformed nanoscale building blocks. Then, the novel properties and emerging applications of the 2D patterned nanostructures based on MCCs in various fields, such as photonics, plasmonics, SERS, antireflection, surface wetting, biological and chemical sensing, solar cells, photocatalysis, field emission, biomimetic fabrication, and other biological and electronic applications, are summarized. An outlook on future developments in this area is also provided. © 2011 Elsevier Ltd.


Shao L.-M.,CAS Beijing National Laboratory for Molecular | Jing X.-P.,CAS Beijing National Laboratory for Molecular
Journal of Luminescence | Year: 2011

The phosphors in the system Y3-xAl5-yO 12:xCe3,yCr3 were synthesized by solid-state reactions and their photoluminescence properties were investigated. These phosphors have absorption in the visible light region and give luminescence in the far-red region (∼688 nm), which are suitable for the application in the device of luminescent solar concentrator (LSC). In these phosphors, Ce 3 located at Y3 site can effectively transfer its absorbed energy to Cr3 at Al3 site. © 2011 Elsevier B.V. All rights reserved.


Cheng Y.-J.,National Chiao Tung University | Hsieh C.-H.,National Chiao Tung University | He Y.,CAS Beijing National Laboratory for Molecular | Hsu C.-S.,National Chiao Tung University | Li Y.,CAS Beijing National Laboratory for Molecular
Journal of the American Chemical Society | Year: 2010

A poly(3-hexylthiophene) (P3HT)-based inverted solar cell using indene-C60 bis-adduct (ICBA) as the acceptor achieved a high open-circuit voltage of 0.82 V due to ICBA's higher-lying lowest unoccupied molecular orbital level, leading to an exceptional power-conversion efficiency (PCE) of 4.8%. By incorporating a cross-linked fullerene interlayer, C-PCBSD, to further modulate the interface characteristics, the ICBA:P3HT-based inverted device exhibited an improved short-circuit current and fill factor, yielding a record high PCE of 6.2%. © 2010 American Chemical Society.


Xie W.J.,CAS Beijing National Laboratory for Molecular | Gao Y.Q.,CAS Beijing National Laboratory for Molecular
Faraday Discussions | Year: 2013

Using molecular dynamics simulations, we investigated effects of inorganic salts on the structure and dynamics of a short α,β-polypeptide, BBA5. The simulations showed that three model salts, NaI, NaF, and Na 2SO3, have very different effects on the structure of the polypeptide. The addition of NaI to the aqueous solution caused denaturation and significantly weakened hydrogen bonds of the polypeptide. Na2SO 3 strengthened the hydrophobic interactions and increased hydrogen bonding of the polypeptide. Preferred binding of Na+ to the backbone carbonyl groups of BBA5 occurred in the NaI solution, consistent with the weakened protein backbone hydrogen bonds, whereas Na+ is excluded more from the vicinity of the protein backbone in the Na2SO 3 solution. This difference in Na+ binding correlates well with the different propensities of the counter ions approaching the protein surface: SO3 2- is much more strongly expelled from the protein apolar surface than I-, and demonstrates the importance of cation-anion cooperativity in affecting protein structures. The binding of the two salts to and their effects on the hydration of the protein surface depends strongly on the polarity of the latter. However, both salts reduce the flexibility of the polypeptide and the fluctuation of its hydration layer. These simulations showed that the chaotropic NaI affects protein structure mainly through a direct binding of Na+ to the backbone and I- to the protein surface. The main effect of Na2SO3 manifests in strengthening the hydrophobic interaction and consequently the hydrogen bonding of the protein, more likely through an "indirect" mechanism. In addition, the simulations showed that NaF has a similar effect as Na 2SO3 (but weaker than the latter, consistent with their positions in the Hofmeister series). © 2013 The Royal Society of Chemistry.


Liu Z.,CAS Beijing National Laboratory for Molecular | Wang J.,CAS Beijing National Laboratory for Molecular | Wang J.,Chinese Academy of Sciences
Journal of Organic Chemistry | Year: 2013

Cross-coupling reactions involving metal-carbene are emerging as a new type of carbon-carbon bond-forming reaction. The aim of this JOCSynopsis is to provide an overview of the most recent development of these reactions, focusing on the use of diazo compounds (or in situ formed diazo compounds from N-tosylhydrazones) as carbene precursors. In addition, the integration of this type of reaction with C-H bond functionalization is also surveyed. © 2013 American Chemical Society.


Chen X.-Y.,CAS Beijing National Laboratory for Molecular | Ye S.,CAS Beijing National Laboratory for Molecular
Synlett | Year: 2013

This account summarizes recent research in our group on the development of N-heterocyclic carbene (NHC) catalyzed cycloaddition reactions of ketenes. The NHCs were found to be efficient catalysts for the enantioselective [2+2]-, [2+2+2]-, [3+2]-, and [4+2]-cycloaddition reactions of ketenes with various electrophiles, such as imines, carbonyl compounds, oxaziridines, oxodienes and azadienes. The NHC-catalyzed [4+2] cycloaddition of α,β-unsaturated acyl chlorides was also investigated. 1 Introduction 2 [2+2] Cycloaddition of Ketenes 2.1 With Carbon-Nitrogen Double Bonds 2.2 With Carbon-Oxygen Double Bonds 2.3 With Oxygen-Nitrogen and Nitrogen-Nitrogen Double Bonds 2.4 With X=Y=Z Bonds 3 [3+2] Cycloaddition of Ketenes 4 [4+2] Cycloaddition of Ketenes 5 [4+2] Annulation of Unsaturated Acyl Chlorides 6 Conclusions and Outlook. © 2013 Georg Thieme Verlag Stuttgart . New York.


Liu J.,CAS Beijing National Laboratory for Molecular | Jia G.,CAS Beijing National Laboratory for Molecular
Journal of Genetics and Genomics | Year: 2014

RNA methylation modifications have been found for decades of years, which occur at different RNA types of numerous species, and their distribution is species-specific. However, people rarely know their biological functions. There are several identified methylation modifications in eukaryotic messenger RNA (mRNA), such as N7-methylguanosine (m7G) at the cap, N6-methyl-2'-O-methyladenosine (m6Am), 2'-O-methylation (Nm) within the cap and the internal positions, and internal N6-methyladenosine (m6A) and 5-methylcytosine (m5C). Among them, m7G cap was studied more clearly and found to have vital roles in several important mRNA processes like mRNA translation, stability and nuclear export. m6A as the most abundant modification in mRNA was found in the 1970s and has been proposed to function in mRNA splicing, translation, stability, transport and so on. m6A has been discovered as the first RNA reversible modification which is demethylated directly by human fat mass and obesity associated protein (FTO) and its homolog protein, alkylation repair homolog 5 (ALKBH5). FTO has a special demethylation mechanism that demethylases m6A to A through two over-oxidative intermediate states: N6-hydroxymethyladenosine (hm6A) and N6-formyladenosine (f6A). The two newly discovered m6A demethylases, FTO and ALKBH5, significantly control energy homeostasis and spermatogenesis, respectively, indicating that the dynamic and reversible m6A, analogous to DNA and histone modifications, plays broad roles in biological kingdoms and brings us an emerging field "RNA Epigenetics". 5-methylcytosine (5mC) as an epigenetic mark in DNA has been studied widely, but m5C in mRNA is seldom explored. The bisulfide sequencing showed m5C is another abundant modification in mRNA, suggesting that it might be another RNA epigenetic mark. This review focuses on the main methylation modifications in mRNA to describe their formation, distribution, function and demethylation from the current knowledge and to provide future perspectives on functional studies. © 2013.


Duan R.,Huazhong University of Science and Technology | Zuo X.,CAS Shanghai Institute of Applied Physics | Wang S.,CAS Beijing National Laboratory for Molecular | Quan X.,No. 1 Hospital | And 5 more authors.
Journal of the American Chemical Society | Year: 2013

Through rational design of a functional molecular probe with high sequence specificity that takes advantage of sensitive isothermal amplification with simple operation, we developed a one-pot hairpin-mediated quadratic enzymatic amplification strategy for microRNA (miRNA) detection. Our method exhibits ultrahigh sensitivity toward miR-21 with detection limits of 10 fM at 37 C and 1 aM at 4 C, which corresponds to nine strands of miR-21 in a 15 μL sample, and it is capable of distinguishing among miRNA family members. More importantly, the proposed approach is also sensitive and selective when applied to crude extractions from MCF-7 and PC3 cell lines and even patient tissues from intraductal carcinoma and invasive ductal carcinoma of the breast. © 2013 American Chemical Society.


Wang X.,CAS Beijing National Laboratory for Molecular | Liu M.,CAS Beijing National Laboratory for Molecular
Chemistry - A European Journal | Year: 2014

Although solvent is the major component of the gel, it still remains unclear how the solvent molecules take part in the formation of the gel nanostructures in many gels. In this study it was observed that the vicinal effect on gel formation as well as their nanostructures, that is, the vicinal solvent molecules to the gelator, determine the molecular packing and their subsequent structures and properties. A naphthylacryl-conjugated L-glutamide gelator was found to form organogels in various solvents and nanofiber structures. While the nanofibers from other solvents could not show any further reaction, the gel from the alcohol could undergo topochemical [2+2] cycloaddition under photoirradiation and resulted in toruloid nanostructures. Various pure alcohol solvents from methanol to pentanol were found to show a similar property. Interestingly, switching from a single alcohol solvent to mixed solvents of alcohol with miscible or immiscible non-alcohol solvents could still cause the same change, showing the vicinal effect of alcohol on controlling the molecular packing as well as the structural transformation. More interestingly, when nanofiber xerogel, obtained from non-alcohol solvents, was exposed to alcohol vapor, the nanofiber was transferred into nanotoruloid. These results provide a new insight into the gelator-solvent interaction in soft gels. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zhou B.,CAS Beijing National Laboratory for Molecular | Chen H.,CAS Institute of Chemistry | Wang C.,CAS Beijing National Laboratory for Molecular
Journal of the American Chemical Society | Year: 2013

The first manganese-catalyzed aromatic C-H alkenylation with terminal alkynes is described. The procedure features an operationally simple catalyst system containing commercially available MnBr(CO)5 and dicyclohexylamine (Cy2NH). The reaction occurs readily in a highly chemo-, regio-, and stereoselective manner delivering anti-Markovnikov E-configured olefins in high yields. Experimental study and DFT calculations reveal that (1) the reaction is initiated by a C-H activation step via the cooperation of manganese and base; (2) manganacycle and alkynylmanganese species are the key reaction intermediates; and (3) the ligand-to-ligand H-transfer and alkynyl-assisted C-H activation are the key steps rendering the reaction catalytic in manganese. © 2013 American Chemical Society.


Shao J.-Y.,CAS Beijing National Laboratory for Molecular | Zhong Y.-W.,CAS Beijing National Laboratory for Molecular
Chemistry - A European Journal | Year: 2014

A common bridging ligand, 3,3 ,5,5 -tetrakis(N-methylbenzimidazol-2-yl) biphenyl, and four terpyridine terminal ligands with various substituents (amine, tolyl, nitro, and ester groups) have been used to synthesize ten cyclometalated diruthenium complexes 12+-102+. Among them, compounds 12+-62+ are redox nonsymmetric, and others are symmetric. These complexes show two RuIII/II processes and an intervalence charge transfer (IVCT) transition in the one-electron oxidized state. The potential separation (ΔE) of 12+-102+ has been correlated to the energy difference ΔG0, the energy of the IVCT band Eop, and the ground-state delocalization coefficient α2. Time-dependent (TD)DFT calculations suggest that the absorptions in the visible region of 12+-62+ are mainly associated with the metal-to-ligand charge-transfer transitions from both ruthenium ions and to both terminal ligands and the bridging ligand. However, the energies of these transitions vary significantly. DFT calculations have been performed on 12+-62+ and 13+-63+ to give information on the electronic structures and spin populations of the mixed-valent compounds. The TDDFT-predicted IVCT excitations reproduce well the experimental trends in transition energies. In addition, three monoruthenium complexes have been synthesized for a comparison study. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zhang Z.,Huazhong University of Science and Technology | Xiao F.,Huazhong University of Science and Technology | Guo Y.,CAS Beijing National Laboratory for Molecular | Wang S.,Huazhong University of Science and Technology | Liu Y.,CAS Beijing National Laboratory for Molecular
ACS Applied Materials and Interfaces | Year: 2013

We reported the development of a new type of multifunctional titanium dioxide (TiO2)-graphene nanocomposite hydrogel (TGH) by a facile one-pot hydrothermal approach and explored its environmental and energy applications as photocatalyst, reusable adsorbents, and supercapacitor. During the hydrothermal reaction, the graphene nanosheets and TiO2 nanoparticles self-assembled into three-dimensional (3D) interconnected networks, in which the spherical nanostructured TiO2 nanoparticles with uniform size were densely anchored onto the graphene nanosheets. We have shown that the resultant TGH displayed the synergistic effects of the assembled graphene nanosheets and TiO2 nanoparticles and therefore exhibited a unique collection of physical and chemical properties such as increased adsorption capacities, enhanced photocatalytic activities, and improved electrochemical capacitive performance in comparison with pristine graphene hydrogel and TiO2 nanoparticles. These features collectively demonstrated the potential of 3D TGH as an attractive macroscopic device for versatile applications in environmental and energy storage issues. © 2013 American Chemical Society.


Zhao X.,CAS Beijing National Laboratory for Molecular | Qi L.,CAS Beijing National Laboratory for Molecular
Nanotechnology | Year: 2012

A rapid one-pot synthesis of hierarchical ZnO hollow spheres consisting of nanoparticles was realized by a facile microwave-assisted solvothermal method using ethanol as the solvent. According to the time-dependent observation of the formation process, a tentative mechanism based on ethyl acetate bubble-templating self-assembly of ZnO nanoparticles was proposed for the formation of the ZnO hollow spheres. Compared with the conventional heating, the microwave irradiation resulted in a significantly shortened reaction time (within 30min) and considerably improved quality of the ZnO hollow spheres, such as narrower size distribution and more regular morphology, owing to the high heating rate and thus the accelerated reaction rate. It was shown that the microwave-assisted synthesis of ZnO nanostructures with tunable morphologies can be realized by judicious selection of appropriate solvents. The obtained ZnO hollow spheres exhibited an excellent adsorption capacity towards Cr(VI) ions in water because of their high surface area for adsorption and a good ability to preserve the accessible surface. © 2012 IOP Publishing Ltd.


He Y.,CAS Beijing National Laboratory for Molecular | He Y.,University of Chinese Academy of Sciences | Chen H.-Y.,Solarmer Energy, Inc. | Hou J.,Solarmer Energy, Inc. | Li Y.,CAS Beijing National Laboratory for Molecular
Journal of the American Chemical Society | Year: 2010

Polymer solar cells (PSCs) are commonly composed of a blend film of a conjugated polymer donor and a soluble C60 derivative acceptor sandwiched between an ITO anode and a low-workfunction metal cathode. Poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C-61-butyric acid methyl ester (PCBM) are the most widely used donor and acceptor materials, respectively. However, the low LUMO energy level of PCBM limits the open circuit voltage (Voc) of the P3HT-based PSCs to ca. 0.6 V. Here we synthesized a new soluble C60 derivative, indene - C60 bisadduct (ICBA), with a LUMO energy level 0.17 eV higher than that of PCBM. The PSC based on P3HT with ICBA as acceptor shows a higher Voc of 0.84 V and higher power conversion efficiency (PCE) of 5.44% under the illumination of AM1.5, 100 mW/cm2, while the PSC based on P3HT/PCBM displays a Voc of 0.58 V and PCE of 3.88% under the same experimental conditions. The results indicate that ICBA is an alternative high-performance acceptor and could be widely used in high-performance PSCs. © 2010 American Chemical Society.


Li Q.,CAS Beijing National Laboratory for Molecular | Yu Z.-X.,CAS Beijing National Laboratory for Molecular
Journal of the American Chemical Society | Year: 2010

C-H activation followed by addition to alkenes is challenging in the current C-H activation/functionalization field. We report herein an unprecedented diene-assisted transition-metal-catalyzed activation of allylic C-H bonds and their subsequent insertion into the alkene moieties of conjugated dienes. This novel C-H activation/alkene insertion reaction provides an efficient way to synthesize polysubstituted tetrahydropyrroles, tetrahydrofurans, and cyclopentanes with quaternary carbon centers. Preliminary mechanistic studies using D-labeling experiments have revealed that allylic C-H activation and alkene insertion are reversible steps, whereas the reductive elimination step, which is the final and the rate-determining step of the catalytic cycle, is irreversible. © 2010 American Chemical Society.


Yu D.-G.,CAS Beijing National Laboratory for Molecular | Shi Z.-J.,CAS Beijing National Laboratory for Molecular | Shi Z.-J.,Chinese Academy of Sciences
Angewandte Chemie - International Edition | Year: 2011

Working together: A new approach of mutual activation between naphtholates and aryl boronic acid derivatives by the formation of borates to facilitate the Suzuki-Miyaura coupling through direct cleavage of the sp 2 C-O bond by nickel catalysis is described (see scheme; R′: annulated ring system). Various naphtholates and aryl boronic acid derivatives could be directly coupled in good yields. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Liu Y.,CAS Beijing National Laboratory for Molecular | Du H.,CAS Beijing National Laboratory for Molecular
Journal of the American Chemical Society | Year: 2013

A metal-free direct hydrogenation of pyridines was successfully realized by using homogeneous borane catalysts generated from alkenes and HB(C 6F5)2 via in situ hydroboration. The reaction affords a broad range of piperidines in high yields with excellent cis stereoselectivities. © 2013 American Chemical Society.