Homobimetallic rhodium NHC complexes as versatile catalysts for hydrosilylation of a multitude of substrates in the presence of ambient air

Two recently reported air- and water-stable di-Rh complexes based on 1,3-bis(3′-butylbenzimidazol-2′-ylidene)benzene were utilized as catalysts for hydrosilylation. Among the substrates investigated were aldehydes, ketones, α,β-unsaturated carbonyls, acyl chlorides, nitriles, alkenes, nitro groups, isocyanates, and tertiary amides. Additionally, carbon dioxide underwent hydrosilylation to produce dimethylphenylsilylformate. The catalysts compared well to other previously reported hydrosilylation catalysts, and the Rh-Cl catalyst was found to be faster and more selective than the Rh-I complex in each case.