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Bouden S.,University Paris Diderot | Gomez-Mingot M.,University Paris Diderot | Gomez-Mingot M.,CNRS Chemistry of Biological Processes Laboratory | Randriamahazaka H.,University Paris Diderot | Ghilane J.,University Paris Diderot
Analytical Chemistry | Year: 2016

A simple and general route for the immobilization of molecules containing ionic liquids framework was described. The proposed approach is inspired from the classical synthesis of ionic liquid and labeled surface-initiated synthesis of molecules bearing ionic liquid components. In the first step, bromide end layer was electrochemically grafted onto the electrode surface followed by its reaction with imidazole derivatives. The generated modified materials were characterized by electrochemistry and by X-ray photoelectron spectroscopy (XPS). As a result, molecule-based ionic liquids were successfully attached onto electrode material. The possibility to perform an anion-exchange reaction within the layer was demonstrated. Furthermore, the proposed surface functionalization approach was successfully performed without requiring the synthesis of any intermediate. The generated structures provide multifunctional systems containing ions, immobilized cation and mobile anion, and redox species. © 2015 American Chemical Society. Source

Kaeffer N.,CNRS Chemistry and Biology of Metals Laboratory | Queyriaux N.,CNRS Chemistry and Biology of Metals Laboratory | Chavarot-Kerlidou M.,CNRS Chemistry and Biology of Metals Laboratory | Fontecave M.,CNRS Chemistry of Biological Processes Laboratory | Artero V.,CNRS Chemistry and Biology of Metals Laboratory
Actualite Chimique | Year: 2015

The production of solar fuels from sunlight, water and carbon dioxide, all three being abundant and renewable resources, is an appealing solution to the energetic challenge of our society. Photosynthesis, the process developed by nature to convert sunlight into biomass, is an inspiration for the design of new and sustainable photocatalytic systems based on Earth-abundant elements, as a way to store solar energy into chemical energy. This field is called artificial photosynthesis and develops at the interface between synthetic chemistry, biochemistry and materials science. Source

Mellot-Draznieks C.,CNRS Chemistry of Biological Processes Laboratory
Molecular Simulation | Year: 2015

The purpose of this article is to consider some recent developments in the area of the computational chemistry of metal-organic frameworks (MOFs), and more specifically on their crystal structure prediction and electronic structures. We intend here to illustrate how computational approaches might be powerful tool for the discovery of new families of hybrid frameworks, helping to understand their often complex energy landscapes. Also, MOFs have attracted a lot of attention due to their potential use for photocatalysis and optoelectronic, making it necessary to develop strategies to control their electronic structures. We will show how recent computational studies in this area have allowed a better understanding of their electronic properties and their potential tunability, highlighting when they have given successful guidelines for the discovery of novel MOFs with targeted properties. © 2015 Taylor & Francis. Source

Aussel L.,Aix - Marseille University | Pierrel F.,CNRS Chemistry and Biology of Metals Laboratory | Loiseau L.,Aix - Marseille University | Lombard M.,CNRS Chemistry of Biological Processes Laboratory | And 2 more authors.
Biochimica et Biophysica Acta - Bioenergetics | Year: 2014

Ubiquinone, also called coenzyme Q, is a lipid subject to oxido-reduction cycles. It functions in the respiratory electron transport chain and plays a pivotal role in energy generating processes. In this review, we focus on the biosynthetic pathway and physiological role of ubiquinone in bacteria. We present the studies which, within a period of five decades, led to the identification and characterization of the genes named ubi and involved in ubiquinone production in Escherichia coli. When available, the structures of the corresponding enzymes are shown and their biological function is detailed. The phenotypes observed in mutants deficient in ubiquinone biosynthesis are presented, either in model bacteria or in pathogens. A particular attention is given to the role of ubiquinone in respiration, modulation of two-component activity and bacterial virulence. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference. © 2014 Elsevier B.V. Source

Ciantar M.,French Institute of Petroleum | Mellot-Draznieks C.,CNRS Chemistry of Biological Processes Laboratory | Nieto-Draghi C.,French Institute of Petroleum
Journal of Physical Chemistry C | Year: 2015

A kinetic Monte Carlo (kMC) approach combined with density functional theory (DFT) calculations is used to examine the effects of molecular diffusion and synthesis parameters (pH 7-12) as well as initial monomer concentration (0.01-1 mol L-1) for a silicate oligomerization model. To implement this approach, we have adapted the open source kMC SPPARKS software in order to simulate the early stages involved in zeolite formation and more generally kinetically driven reactional systems, using a variety of lattice models (fcc/octahedral/tetrahedral, i.e., fcc/oct/tet). First, these adaptations were validated with kinetically driven reactional systems of the "Lodka" model, providing an excellent match with the analytical solution of the reactive system. The calculations reveal that both the lattice complexity and the diffusion coefficients of species have an impact on the steady state concentration (ssc) of oligomers in solution. Second, the approach is further applied to the early stages of silicate oligomerization using chemical pathways (activation barriers and associated prefactors) taken from the literature. Besides the expected impact of key input parameters (amplitudes of energy barriers, influence of water molecules in reaction pathways, pH, etc.), we demonstrate the impact of diffusion (viscosity of the clear solution) on the ssc of silicate oligomers. Considering that the kMC model is limited by the frequencies of reactional rare events, we find that when diffusional frequencies are much larger than reactional ones, the system diffuses instead of reacting. In that respect our calculations suggest that the magnitude of the diffusion coefficient determines the relative ssc of cyclic vs linear oligomers with a transition regime around of 10-14 m2 s-1 under the reaction conditions studied here (pH 9, 350 K, and initial concentration of 1 mol L-1). © 2015 American Chemical Society. Source

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