Person: Cano Rico, Israel
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First Name
Israel
Last Name
Cano Rico
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Inorgánica
Area
Química Inorgánica
Identifiers
2 results
Search Results
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Item Characterization of Secondary Phosphine Oxide Ligands on the Surface of Iridium Nanoparticles(Physical Chemistry Chemical Physics, 2017) Cano Rico, Israel; Martínez-Prieto, Luis ; Fazzini, Pier ; Coppel, Yannick; Chaudret, Bruno; Leeuwen, Piet vanThe synthesis of iridium nanoparticles (IrNPs) ligated by various secondary phosphine oxides (SPOs) is described. This highly reproducible and simple method via H2 reduction produces well dispersed, small nanoparticles (NPs), which were characterized by the state-of-the-art techniques, such as TEM, HRTEM, WAXS and ATR FT-IR spectroscopy. In particular, multinuclear solid state MAS-NMR spectroscopy with and without cross polarization (CP) enabled us to investigate the different binding modes adopted by the ligand at the nanoparticle surface, suggesting the presence of three possible types of coordination: as a purely anionic ligand Ir–P(O)R2, as the neutral acid R2P–O–H and as a monoanionic bidentate H-bonded dimer R2P–O–H···O=PR2. Specifically, the higher basicity of the dicyclohexyl system leads to the formation of IrNPs in which the bidentate binding mode is most abundant. Such cyclohexyl groups are bent towards the edges, as is suggested by the study of 13CO coordination on the NP surface. This study also showed that the number of surface sites on faces available for bridging CO molecules is higher than the number of sites for terminal CO species on edges and apices, which is unexpected taking into account the small size of the nanoparticles. In addition, the IrNPs present a high chemoselectivity in the hydrogenation of cinnamaldehyde to the unsaturated alcohol.Item An Iridium–SPO Complex as Bifunctional Catalyst for the Highly Selective Hydrogenation of Aldehydes(Catalysis Science & Technology, 2017) Cano Rico, Israel; Martínez-Prieto, Luis ; Vendier, Laure; Leeuwen, Piet vanA secondary phosphine oxide (SPO) ligand (tert-butyl(phenyl)phosphine oxide) was employed to generate an Ir–SPO complex which shows a particular ability to activate dihydrogen under mild conditions without the help of an external base or additive. Such an iridium (I) complex serves as a precursor for homogeneous catalysis since under H2 it is converted to a mixture of several iridium (III) hydride species that are the active catalysts. This system was found to be a highly active catalyst for the hydrogenation of substituted aldehydes, giving very high conversions and chemoselectivities for a wide range of substrates. The SPO ligand presumably plays a key role in the catalytic process through heterolytic cleavage of H2 by metal–ligand cooperation. In addition, an exhaustive characterization of the different iridium hydride species was performed by 1D and 2D NMR spectroscopy. The oxidative addition of H2 to the Ir(I)–SPO complex is highly stereoselective, as all generated Ir(III) hydrides are homochiral. Finally, the crystal structure, as determined by X-Ray Diffraction, of a dinuclear iridium (III) hydride complex is described.