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Gonzalez-Galvez D.,Institute of Chemical Research of Catalonia | Lara P.,CNRS Coordination Chemistry | Lara P.,Toulouse 1 University Capitole | Rivada-Wheelaghan O.,University of Seville | And 5 more authors.
Catalysis Science and Technology | Year: 2013

The application of ruthenium nanoparticles (RuNPs) stabilized by the N-heterocyclic carbenes (NHC) N,N′-di(tert-butyl)imidazol-2-ylidene (ItBu) and 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene IPr as catalysts in the hydrogenation of several substrates is reported under various reaction conditions (solvent, substrate concentration, substrate/metal ratio, temperature). The RuNHC nanoparticles are active catalysts in the hydrogenation of aromatics and show an interesting ligand effect, RuIPr NPs being generally more active than RuItBu. © The Royal Society of Chemistry 2013.

Baquero E.A.,University of Alcalá | Tricard S.,Laboratoire Of Physique Et Chimie Of Nano Objets | Flores J.C.,University of Alcalá | De Jesffls E.,University of Alcalá | Chaudret B.,Laboratoire Of Physique Et Chimie Of Nano Objets
Angewandte Chemie - International Edition | Year: 2014

Controlling the synthesis of stable metal nanoparticles in water is a current challenge in nanochemistry. The strategy presented herein uses sulfonated N-heterocyclic carbene (NHC) ligands to stabilize platinum nanoparticles (PtNPs) in water, under air, for an indefinite time period. The particles were prepared by thermal decomposition of a preformed molecular Pt complex containing the NHC ligand and were then purified by dialysis and characterized by TEM, high-resolution TEM, and spectroscopic techniques. Solidstate NMR studies showed coordination of the carbene ligands to the nanoparticle surface and allowed the determination of a 13C-195Pt coupling constant for the first time in a nanosystem (940 Hz). Additionally, in one case a novel structure was formed in which platinum(II) NHC complexes form a second coordination sphere around the nanoparticle. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lara P.,CNRS Coordination Chemistry | Lara P.,Toulouse 1 University Capitole | Ayvali T.,CNRS Coordination Chemistry | Ayvali T.,Toulouse 1 University Capitole | And 7 more authors.
Dalton Transactions | Year: 2013

Diphenylphosphinobutane (dppb) stabilized bimetallic RuPt nanoparticles were prepared by co-decomposition of [Ru(COD)(COT)] [(1,5-cyclooctadiene)(1,3,5- cyclooctatriene)ruthenium] and [Pt(CH3)2(COD)] [dimethyl(1,5-cyclooctadiene) platinum(ii)] organometallic precursors under mild conditions (room temperature, 3 bar of dihydrogen) and in the presence of dppb. The determination of the nanoparticles' chemical composition was made possible thanks to a combination of several characterization techniques (HREM, STEM-HAADF, WAXS, EXAFS, IR, NMR) associated with surface reactivity studies based on simple catalytic reactions. The obtained nanoparticles display a ruthenium rich core and a disordered shell containing both ruthenium and platinum. The results were compared with those obtained on nanoparticles of similar size and composition but not containing ligands. The complexity observed in the present structure of these nanoparticles arises from the high chemical affinity of the diphosphine ligand used as a stabilizer for both metals. © 2013 The Royal Society of Chemistry.

Lara P.,CNRS Coordination Chemistry | Lara P.,Toulouse 1 University Capitole | Casanove M.-J.,CNRS Toulouse Center for Materials Elaboration and Structural Studies | Casanove M.-J.,Toulouse 1 University Capitole | And 6 more authors.
Journal of Materials Chemistry | Year: 2012

Core-shell small RuPt nanoparticles stabilized by a polymer (polyvinylpyrrolidone, PVP) have been prepared by co-decomposition of [Ru(COD)(COT)] [(1,5-cyclooctadiene)(1,3,5-cyclooctatriene)ruthenium] and [Pt(CH 3) 2(COD)] [dimethyl(1,5-cyclooctadiene)platinum(ii)] organometallic complexes at room temperature. The control of the metal segregation is made possible by the difference in the decomposition temperature of the metal precursors, giving rise to a heterogeneous nucleation process. The structural composition of these nanoparticles has been determined by a combination of techniques (TEM, HREM, WAXS, EXAFS, STEM-HAADF, IR, NMR). In particular, after adsorption of 13CO as a probe molecule, solid-state NMR investigation provided useful information on the chemical segregation in these nanoparticles. © 2012 The Royal Society of Chemistry.

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