Carbohydrate-Derived 1,3-Diphosphite Ligands as Chiral Nanoparticle Stabilizers: Promising Catalytic Systems for Asymmetric Hydrogenation

Metallic Ru, Rh, and Ir nanoparticles were prepared by the decomposition of organometallic precursors under H2 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 nano...

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Bibliographic Details
Published in:ChemSusChem 2009-08, Vol.2 (8), p.769-779
Main Authors: Gual, Aitor, Godard, Cyril, Philippot, Karine, Chaudret, Bruno, Denicourt-Nowicki, Audrey, Roucoux, Alain, Castillón, Sergio, Claver, Carmen
Format: Article
Language:English
Subjects:
Anisoles - chemistry
carbohydrates
Carbohydrates - chemistry
Catalysis
Chemical Sciences
diphosphites
Drug Design
Hydrogenation
Ligands
Metal Nanoparticles - chemistry
nanoparticles
Particle Size
Phosphites - chemistry
Stereoisomerism
Substrate Specificity
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Summary:Metallic Ru, Rh, and Ir nanoparticles were prepared by the decomposition of organometallic precursors under H2 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. Metallic Ru, Rh, and Ir nanoparticles are prepared by the decomposition of organometallic precursors in the presence of 1,3‐diphosphite ligands as stabilizing agents. These nanoparticles are shown to be active in the hydrogenation of m‐ and o‐methylanisole.
ISSN:1864-5631
1864-564X
DOI:10.1002/cssc.200900079