title: Chiral ammonium-capped rhodium(0) nanocatalysts: synthesis, characterization, and advances in asymmetric hydrogenation in neat water.
abstract: Optically active amphiphilic compounds derived from N-methylephedrine, N-methylprolinol, or cinchona derivatives possessing bromide or chiral lactate counterions were efficiently used as protective agents for rhodium(0) nanoparticles. The full characterization of these surfactants and the obtained nanocatalysts was performed by means of different techniques. These spherical nanoparticles, with sizes between 0.8-2.5 nm depending on the stabilizer, were evaluated in the hydrogenation of model substrates in neat water as a green solvent. The rhodium catalysts showed relevant kinetic properties, but modest enantiomeric excess values of up to 13 % in the hydrogenation of ethyl pyruvate. They were also investigated in the hydrogenation of disubstituted arenes, such as m-methylanisole, providing interesting catalytic activities and a preferential cis selectivity of around 80 %; however, no asymmetric induction was observed.
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, Rennes, France.
authors.forename: Elodie Guyonnet
authors.initials: EG
authors.lastname: Bilé
authors.forename: Elodie
authors.initials: E
authors.lastname: Cortelazzo-Polisini
authors.forename: Audrey
authors.initials: A
authors.lastname: Denicourt-Nowicki
authors.forename: Rita
authors.initials: R
authors.lastname: Sassine
authors.forename: Franck
authors.initials: F
authors.lastname: Launay
authors.forename: Alain
authors.initials: A
authors.lastname: Roucoux
mesh_terms: D000840:Anisoles / Q000737:chemistry; D060326:Chemistry Techniques, Synthetic / Q000379:methods*; D006865:Hydrogenation; D049329:Nanostructures / Q000737:chemistry*; D055620:Optical Phenomena; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012238:Rhodium / Q000737:chemistry*; D012492:Salts / Q000737:chemistry; D012995:Solubility; D013237:Stereoisomerism; D013501:Surface-Active Agents / Q000138:chemical synthesis / Q000737:chemistry; D013535:Suspensions; D014867:Water / Q000737:chemistry*
chemical_list: D000840:Anisoles; D000644:Quaternary Ammonium Compounds; D012492:Salts; D013501:Surface-Active Agents; D013535:Suspensions; D014867:Water; C428434:2-methylanisole; D012238:Rhodium