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Carbohydrate‐Derived 1,3‐Diphosphite Ligands as Chiral Nanoparticle Stabilizers: Promising Catalytic Systems for Asymmetric Hydrogenation
Author(s) -
Gual Aitor,
Godard Cyril,
Philippot Karine,
Chaudret Bruno,
DenicourtNowicki Audrey,
Roucoux Alain,
Castillón Sergio,
Claver Carmen
Publication year - 2009
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.200900079
Subject(s) - catalysis , selectivity , nanoparticle , chemistry , asymmetric hydrogenation , decomposition , metal , catalytic hydrogenation , combinatorial chemistry , organic chemistry , enantioselective synthesis , materials science , nanotechnology
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.