title: Carbohydrate-derived 1,3-diphosphite ligands as chiral nanoparticle stabilizers: promising catalytic systems for asymmetric hydrogenation.
abstract: Metallic Ru, Rh, and Ir nanoparticles were prepared by the decomposition of organometallic precursors under H(2) pressure in the presence of 1,3-diphosphite ligands, derived from carbohydrates, as stabilizing agents. Structural modifications to the diphosphite backbone were found to influence the nanoparticles' size, dispersion, and catalytic activity. In the hydrogenation of o- and m-methylanisole, the Rh nanoparticles showed higher catalytic activity than the corresponding Ru nanoparticles. The Ir nanoparticles presented the lowest catalytic activity of the series. In all cases, the hydrogenation of o-methylanisole gave total selectivity for the cis-product, however, the ee of the product was always less than 6 %. A maximum of 81 % cis-selectivity was obtained for the hydrogenation of m-methylanisole, however, no asymmetric induction was observed. These results show that the catalytic activity is affected by a combination of influences from the substrate, the diphosphite ligands, and the metallic nanoparticles.
authors: Department de Química Física I Inorgànica, Universitat Rovira I Virigli, Tarragona, Spain.
authors: Aitor
authors: A
authors: Gual
authors: Cyril
authors: C
authors: Godard
authors: Karine
authors: K
authors: Philippot
authors: Bruno
authors: B
authors: Chaudret
authors: Audrey
authors: A
authors: Denicourt-Nowicki
authors: Alain
authors: A
authors: Roucoux
authors: Sergio
authors: S
authors: Castillón
authors: Carmen
authors: C
authors: Claver
mesh_terms: D000840:Anisoles / Q000737:chemistry; D002241:Carbohydrates / Q000737:chemistry*; D002384:Catalysis; D015195:Drug Design; D006865:Hydrogenation; D008024:Ligands; D053768:Metal Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D017905:Phosphites / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D000840:Anisoles; D002241:Carbohydrates; D008024:Ligands; D017905:Phosphites; C060998:anisole