Valencia de Alcántara, Spain
Valencia de Alcántara, Spain

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Blasco S.,Institute Ciencia Molecular | Verdejo B.,Institute Ciencia Molecular | Soriano C.,Institute Ciencia Molecular | Garcia-Espana E.,Institute Ciencia Molecular
Organic and Biomolecular Chemistry | Year: 2015

Interactions of different hydrophilic (His, Asp, Glu,) and hydrophobic (Ala, Phe, Tyr, Trp) amino acids in water with a scorpiand aza-macrocycle (L1) containing a pyridine group in the ring and its derivative (L2) bearing a naphthalene group in the tail have been analysed by potentiometric and calorimetric measurements. Theoretical calculations corroborate that major attractive forces that hold the adduct together are hydrogen bonds and salt-bridges, even though other interactions such as π-stacking or NH+⋯π may contribute in the case of hydrophobic amino acids and L2. Calorimetric measurements indicate that the interactions between L1 and the different amino acids are principally driven by entropy, often associated with solvation/desolvation processes. © 2015 The Royal Society of Chemistry.


Serrano E.S.,Institute Ciencia Molecular
Molecules | Year: 2015

The interaction of the G-2 poly(ethylene imine) dendrimer L, derived from ammonia as initiating core, with Hg(II) and HgCl42- was studied in aqueous solution by means of potentiometric (pH-metric) measurements. Speciation of these complex systems showed that L is able to form a wide variety of complexes including 1:1, 2:1, 3:1 and 3:2 metal-to-ligand species, of different protonation states, as well as the anion complexes [(H7L)HgCl4 ]5+ and [(H8L)HgCl4]6+. The stability of the metal complexes is very high, making L an excellent sequestering agent for Hg(II), over a large pH range, and a promising ligand for the preparation of functionalized activated carbons to be employed in the remediation and the prevention of environmental problems. © 2015 by the authors; licensee MDPI, Basel, Switzerland.


PubMed | Institute Ciencia Molecular
Type: Journal Article | Journal: Molecules (Basel, Switzerland) | Year: 2015

The interaction of the G-2 poly(ethylene imine) dendrimer L, derived from ammonia as initiating core, with Hg(II) and HgCl42- was studied in aqueous solution by means of potentiometric (pH-metric) measurements. Speciation of these complex systems showed that L is able to form a wide variety of complexes including 1:1, 2:1, 3:1 and 3:2 metal-to-ligand species, of different protonation states, as well as the anion complexes [(H7L)HgCl4]5+ and [(H8L)HgCl4]6+. The stability of the metal complexes is very high, making L an excellent sequestering agent for Hg(II), over a large pH range, and a promising ligand for the preparation of functionalized activated carbons to be employed in the remediation and the prevention of environmental problems.


Borin A.C.,University of Sao Paulo | Gobbo J.P.,Institute Ciencia Molecular
International Journal of Quantum Chemistry | Year: 2011

Multiconfigurational second-order perturbation theory (CASSCF//CASPT2) and quadruple-φ¶ ANO-RCC basis sets were employed to investigate the ground and low-lying electronic states of MoB and MoB+. Spectroscopic constants, potential energy curves, wavefunctions, Mulliken population analyses, and ionization energies are given. The ground state of MoB is of X 6φ symmetry (Re = 1.968 Å, ωe = 664 cm-1, and μ = 2.7 D), giving rise to a ω = 7/2 ground state after including spin-orbit coupling. For MoB+, the ground state is computed to be of X7 ∑+ symmetry (Re = 2.224 Å, ωe = 141 cm-1, and μ = 1.2 D), with an adiabatic ionization energy of 7.19 eV and a vertical one of 7.53 eV. © 2010 Wiley Periodicals, Inc.


Bazzicalupi C.,University of Florence | Bianchi A.,University of Florence | Garcia-Espana E.,Institute Ciencia Molecular | Delgado-Pinar E.,Institute Ciencia Molecular
Inorganica Chimica Acta | Year: 2014

Metals have played a fundamental role in the development of supramolecular chemistry. The main steps taken from the pre-supramolecular age to the present time are retraced with a brief description of salient examples from the unconscious use of gold nanoparticle in the preparation of the Lycurgus cup (5th or 4th century B.C.) to the modern use of metals as templates, for the preparation of large self-assembled structures, of molecular sensors, switches, motors and machines, for mimicking biological processes, for tissue and organ imaging or for the application of the Boolean logic at the molecular level. © 2014 Elsevier B.V. All rights reserved.


Belda R.,Institute Ciencia Molecular | Blasco S.,Institute Ciencia Molecular | Verdejo B.,Institute Ciencia Molecular | Jimenez H.R.,University of Valencia | And 5 more authors.
Dalton Transactions | Year: 2013

The new receptor 3,7,11,15,19,23-hexaaza-1(2,6)-pyridinacyclotetracosaphane (L1) containing a complete sequence of propylenic chains has been synthesised. The acid-base behaviour and Cu2+ and Zn2+ coordination have been analysed by potentiometric measurements in 0.15 M NaClO4 for L1 and for the related compounds 3,7,11,14,18,22-hexaaza-1(2,6)- pyridinacyclotricosaphane (L2), 3,7,10,13,16,20-hexaaza-1(2,6)- pyridinacycloheneicosaphane (L3) and 3,7,10,12,15,19-hexaaza-1(2,6)- pyridinacycloicosaphane (L4). The crystal structure of [(CuH4L2) (H2O)(ClO4)](ClO4)5·3H 2O shows an interesting combination of a metal ion coordinated by the pyridine nitrogen atom and the adjacent amine groups of the chain, and a perchlorate anion sitting at the middle of the site defined by the remaining four protonated ammonium groups of L1. Paramagnetic NMR data suggest that imidazole coordinates to the Cu2+ ions as a bridging ligand in a wide pH range. SOD activity for Cu2+-Cu2+ and Cu 2+-Zn2+ complexes with L1-L4 have been measured by NBT assays at pH 7.4, obtaining some of the lowest values so far reported for SOD mimics. SOD activity has also been checked by chemiluminescence assays using polymorphonuclear leukocytes (PMNLs). © 2013 The Royal Society of Chemistry.


Castillo C.E.,University of Cádiz | Manez M.A.,University of Cádiz | Basallote M.G.,University of Cádiz | Clares M.P.,Institute Ciencia Molecular | And 2 more authors.
Dalton Transactions | Year: 2012

The formation of Cu(ii) complexes with two isomeric quinoline-containing scorpiand-type ligands has been studied. The ligands have a tetraazapyridinophane core appended with an ethylamino tail including 2-quinoline (L1) or 4-quinoline (L2) functionalities. Potentiometric studies indicate the formation of stable CuL 2+ species with both ligands, the L1 complex being 3-4 log units more stable than the L2 complex. The crystal structure of [Cu(L1)](ClO 4) 2·H 2O shows that the coordination geometry around the Cu 2+ ions is distorted octahedral with significant axial elongation; the four Cu-N distances in the equatorial plane vary from 1.976 to 2.183 Å, while the axial distances are of 2.276 and 2.309 Å. The lower stability of the CuL2 2+ complex and its capability of forming protonated and hydroxo complexes suggest a penta-dentate coordination of the ligand, in agreement with the type of substitution at the quinoline ring. Kinetic studies on complex formation can be interpreted by considering that initial coordination of L1 and L2 takes place through the nitrogen atom in the quinoline ring. This is followed by coordination of the remaining nitrogen atoms, in a process that is faster in the L1 complex probably because substitution at the quinoline ring facilitates the reorganization. Kinetic studies on complex decomposition provide clear evidence on the occurrence of the molecular motion typical of scorpiands in the case of the L2 complex, for which decomposition starts with a very fast process (sub-millisecond timescale) that involves a shift in the absorption band from 643 to 690 nm. © 2012 The Royal Society of Chemistry.


Dugay J.,Technical University of Delft | Gimenez-Marques M.,Institute Ciencia Molecular | Kozlova T.,Technical University of Delft | Zandbergen H.W.,Technical University of Delft | And 2 more authors.
Advanced Materials | Year: 2015

(Graph Presented) Two-dimensional assemblies of triazole-based spin-crossover nanoparticles (SCO NPs) presenting different morphologies are prepared and electrically characterized. The thermal hysteresis loop in the electrical conductance near room temperature correlates with the NP morphologies and their 2D organization. The unprecedentedly large difference - up to two orders of magnitude - in the electrical conductance of the two spin states is of interest for applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA.


PubMed | Technical University of Delft and Institute Ciencia Molecular
Type: Journal Article | Journal: Advanced materials (Deerfield Beach, Fla.) | Year: 2016

The charge transport properties of SCO [Fe(Htrz)2 (trz)](BF4 ) NPs covered with a silica shell placed in between single-layer graphene electrodes are reported. A reproducible thermal hysteresis loop in the conductance above room-temperature is evidenced. This bistability combined with the versatility of graphene represents a promising scenario for a variety of technological applications but also for future sophisticated fundamental studies.


PubMed | Institute Ciencia Molecular
Type: Journal Article | Journal: Organic & biomolecular chemistry | Year: 2014

Interactions of different hydrophilic (His, Asp, Glu,) and hydrophobic (Ala, Phe, Tyr, Trp) amino acids in water with a scorpiand aza-macrocycle (L1) containing a pyridine group in the ring and its derivative (L2) bearing a naphthalene group in the tail have been analysed by potentiometric and calorimetric measurements. Theoretical calculations corroborate that major attractive forces that hold the adduct together are hydrogen bonds and salt-bridges, even though other interactions such as -stacking or NH(+) may contribute in the case of hydrophobic amino acids and L2. Calorimetric measurements indicate that the interactions between L1 and the different amino acids are principally driven by entropy, often associated with solvation/desolvation processes.

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