Synthesis and structure of triosmium clusters bearing an organosilicon ligand

Abstract

The reactions of 4-methylquinoline-capped triosmium cluster [Os3(CO)9(μ3-η1,κ1-H3CC9H5N)(μ-H)] (1) with various organosilicon ligands of the general formula R´R2SiH have been examined. Treatment of 1 with R´R2SiH in refluxing benzene leads to the stepwise formation of [Os3(CO)9(SiR2R)(μ-η1,κ1-H3CC9H5N)(μ-H)2] (2) and [Os3(CO)8(SiR2R)(μ3-η1,κ1-H3CC9H5N)(μ-H)2] (3), respectively, as confirmed by control experiments. In these reactions, oxidative-addition of the Si single bond H bond to 1 affords 2 whose decarbonylation leads to the formation of 3. X-ray crystallography has been used to determine the molecular structure of the products, while the bonding in them has been investigated by electronic structure calculations. Both 2 and 3 exist as a pair of isomers in solution.