Neutral Dinuclear Copper(I)-NHC Complexes: Synthesis and Application in the Hydrosilylation of Ketones

The synthesis of a class of highly stable neutral dinuclear Cu­(I)-NHC complexes using 1,2,4-triazole as a bridging ligand is described. Various NHCs were used to generate a library of [Cu­(μ-trz)­(NHC)]2 complexes. Interestingly, [Cu­(μ-trz)­(IPr)]2 was found to be highly active in the hydrosilylation of ketones, without the need for an external base or any other additive. A wide range of aryl and alkyl ketones, as well as sterically hindered ketones, was successfully reduced to alcohols using the lowest catalyst loading reported to date.