Synthesis, structural characterisation and catalytic application of dichloro(η 6-p-cymene){diphenyl(3-methyl-2-indolyl)phosphine}ruthenium(II) in the transfer hydrogenation of ketones

The synthesis and investigation of ruthenium complexes containing the relatively unexplored ligand, diphenyl-2-(3-methyl)indolylphosphine, is presented herein. The complexes [RuCl2{PPh2(C9H8N)}3], [Ru2(μ-Cl)3(Cl)(MeCN){PPh2(C9H8N)}4] and [RuCl2(η 6-p-cymeme){PPh2(C9H8N)}] have been studied. Single crystals of the latter two complexes have been prepared and investigated by X-ray crystallography. A detailed examination of [RuCl2(η 6-p-cymeme){PPh2(C9H8N)}] has been carried out. This complex was found to be an active catalyst in the catalytic transfer hydrogenation of ketones.