Paris, France
Paris, France

Chimie ParisTech , also known as ENSCP or Chimie Paris) is an elite chemical science and engineering college founded in 1896, located in the 5th arrondissement of Paris. It is one of the founding members of ParisTech , and Paris science et Lettres – Quartier latin. The students enter the school after highly competitive exams known as the Concours Communs Polytechniques, following at least two years of classes préparatoires. The school is known as France's most selective chemical engineering collegeThe school is a research center hosting nine laboratories which conduct high level research in various fields of chemistry. Wikipedia.

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Zeolitic imidazolate framework ZIF-8 displays flexibility of its structure by rotation of its imidazolate linker. This "swing effect" has been widely described in the literature, both experimentally and theoretically, as a bistable system where the linker oscillates between two structures: "open window" and "closed window". By using quantum chemistry calculations and first-principles molecular dynamics simulations, it is shown that the deformation upon adsorption is in fact continuous upon pore loading, with thermodynamics of packing effects being the reason behind stepped adsorption isotherms experimentally observed. Finally, we study a variant of ZIF-8 with a different linker, highlighting the influence of the linker and the balance of microscopic interactions on the framework's flexibility. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Aubin Y.,CNRS Laboratory of Molecular and Thio-Organic Chemistry | Fischmeister C.,CNRS Chemistry Institute of Rennes | Thomas C.M.,Chimie Paristech | Renaud J.-L.,CNRS Laboratory of Molecular and Thio-Organic Chemistry
Chemical Society Reviews | Year: 2010

The traditional homogeneous access to aromatic amine derivatives is a nucleophilic aromatic substitution of the corresponding aryl halides. The halogen atom is usually relatively inert to amination reaction unless it is activated by the presence of electron withdrawing groups. Consequently, there has been particular emphasis over the past decade on the synthesis of metal complexes that are active catalysts for the preparation of aromatic amines. This tutorial review focuses on the use of metal-based complexes for the direct amination of aryl halides with ammonia. © 2010 The Royal Society of Chemistry.

Thomas C.M.,Chimie Paristech | Lutz J.-F.,Charles Sadron Institute
Angewandte Chemie - International Edition | Year: 2011

Its all in the sequence: The primary structure of poly(lactic-co-glycolic acid) (PLGA), a member of the most widely used class of biodegradable polymers employed in biomedical applications, is demonstrated to strongly influence its degradation properties. Experimental studies evidenced the beneficial effect of ordered monomer sequences on the material properties (see picture). © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ortiz A.U.,Chimie Paristech | Boutin A.,University Pierre and Marie Curie | Fuchs A.H.,Chimie Paristech | Coudert F.-X.,Chimie Paristech
Physical Review Letters | Year: 2012

We performed ab initio calculations of the elastic constants of five flexible metal-organic frameworks (MOFs): MIL-53(Al), MIL-53(Ga), MIL-47, and the square and lozenge structures of DMOF-1. Tensorial analysis of the elastic constants reveals a highly anisotropic elastic behavior, some deformation directions exhibiting very low Young's modulus and shear modulus. This anisotropy can reach a 4001 ratio between the most rigid and weakest directions, in stark contrast to the case of nonflexible MOFs such as MOF-5 and ZIF-8. In addition, we show that flexible MOFs can display extremely large negative linear compressibility. These results uncover the microscopic roots of stimuli-induced structural transitions in flexible MOFs, by linking the local elastic behavior of the material and its multistability. © 2012 American Physical Society.

Adamo C.,Chimie Paristech | Adamo C.,Institut Universitaire de France | Jacquemin D.,Institut Universitaire de France | Jacquemin D.,University of Nantes
Chemical Society Reviews | Year: 2013

In this tutorial review, we show how Time-Dependent Density Functional Theory (TD-DFT) has become a popular tool for computing the signatures of electronically excited states, and more specifically, the properties directly related to the optical (absorption and emission) spectra of molecules. We discuss the properties that can be obtained with widely available programs as well as how to account for the environmental effects (solvent and surfaces) and present recent applications in these fields. We next expose the transformation of the TD-DFT results into chemically intuitive parameters (colours as well as charge-transfer distances). Eventually, the non-specialised reader will find a series of advices and warnings necessary to perform her/his first TD-DFT calculations. © 2013 The Royal Society of Chemistry.

Genet J.-P.,Chimie Paristech | Ayad T.,Chimie Paristech | Ratovelomanana-Vidal V.,Chimie Paristech
Chemical Reviews | Year: 2014

This review covers the literature mainly from 2004 and focuses on the comparison of DIFLUORPHOS with electron-poor and -rich atropisomeric phosphines for metal-catalyzed asymmetric reactions. Improved reactivity and enantioselectivity have been observed with DIFLUORPHOS in the investigations. DIFLUORPHOS has been synthesized on multigram scale according to a general strategy in six steps from the properly functionalized aryl compounds. The key step for establishing the biphenyl framework is the Ullman coupling reaction. The steric evaluation of DIFLUORPHOS 31 and comparison with other atropisomeric diphosphines have been achieved by measuring the dihedral angle of the biaryl skeleton in free and chelated diphosphines.

While the energetic stability of the large number of possible SiO 2 polymorphs has been widely addressed by both experimental and theoretical studies, there is a real dearth of information on their mechanical properties. We performed a systematic study of the elastic properties of 121 pure silica zeolites, including both experimentally synthesized and hypothetical structures, by means of density-functional theory calculations. We found that most frameworks exhibit high elastic anisotropy, and the experimentally synthesized structures are among the most mechanically stable ones. We propose to extend the feasibility criterion proposed in earlier literature to include elastic anisotropy, allowing to further reduce the number of possible targets for synthesis of SiO2 polymorphs. We also predict that a small number of hypothetical pure silica zeolites present large negative linear compressibility (NLC), which we link to the wine-rack motif of their framework. © 2013 The Owner Societies.

Recent years have seen a large increase of the research effort focused on framework materials, including the nowadays-ubiquitous metal-organic frameworks but also dense coordination polymers, covalent organic frameworks, and molecular frameworks. With the quickly increasing number of structures synthesized and characterized, one pattern emerging is the common occurrence of flexibility. More specifically, an important number of framework materials are stimuli-responsive: their structure can undergo changes of large amplitude in response to physical or chemical stimulation. They can display transformations induced by temperature, mechanical pressure, guest adsorption or evacuation, light absorption, etc. and are sometimes referred to as smart materials, soft crystals, or dynamic materials. This Perspective highlights recent progress in this field, showcasing some of the most novel and unusual responses to stimuli, as well as advances in the fundamental understanding of flexible framework materials. © 2015 American Chemical Society.

Robert C.,Chimie Paristech | Thomas C.M.,Chimie Paristech
Chemical Society Reviews | Year: 2013

The creation of polymers by tandem catalysis represents an exciting frontier in materials science. Tandem catalysis is one of the strategies used by Nature for building macromolecules. Living organisms generally synthesize macromolecules by in vivo enzyme-catalyzed chain growth polymerization reactions using activated monomers that have been formed within cells during complex metabolic processes. However, these biological processes rely on highly complex biocatalysts, thus limiting their industrial applications. In order to obtain polymers by tandem catalysis, homogeneous and enzyme catalysts have played a leading role in the last two decades. In the following feature article, we will describe selected published efforts to achieve these research goals. © 2013 The Royal Society of Chemistry.

Coudert F.-X.,Chimie Paristech
Physical Chemistry Chemical Physics | Year: 2010

Predictive analytical methods are crucial tools in the design of adsorptive gas separation processes. While they are widely used for rigid nanoporous solids, there is a lack of flexible materials, including the very topical and promising dynamic metal-organic frameworks (MOFs), which display such eye-catching phenomena as gate opening and breathing. We present here the osmotic framework adsorbed solution theory (OFAST), which predicts the evolution of structural transitions and selectivity upon adsorption of fluid mixtures in flexible nanoporous solids, using as a sole input experimental pure component isotherms. © 2010 the Owner Societies.

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