Cobalt(II) and (I) Complexes of Diphosphine-Ketone Ligands: Catalytic Activity in Hydrosilylation Reactions

The hydrosilylation of unsaturated compounds homogeneously catalyzed by cobalt complexes has gained considerable attention in the last years, aiming at substituting precious metal-based catalysts. In this study, the catalytic activity of well-characterized Co^II and Co^I complexes of the dpbp ligand is demonstrated in the hydrosilylation of 1-octene with phenylsilane. The Co^I complex is the better precatalyst for the mentioned reaction under mild conditions, at 1 mol-% catalyst, 1 h, room temperature, and without solvent, yielding 84 % of octylphenylsilane. Investigation of the substrate scope shows lower performance of the catalyst in styrene hydrosilylation, but excellent results with allylbenzene (84 %) and acetophenone (> 99 %). This catalytic study contributes to the field of cobalt-catalyzed hydrosilylation reactions and shows the first example of catalysis employing the dpbp ligand in combination with a base metal.