Conformationally rigid diphosphine arene–ruthenium(II) complexes as catalysts for transfer hydrogenation of ketones

Abstract

Conformationally rigid [(η 6-arene)Ru(PP)Cl]CF 3SO 3 (arene=C 6H 6 ( 1), p-MeC 6H 5CHMe 2 ( 2), 1,3,5-Me 3C 6H 3 ( 3), and Me 6C 6 ( 4); PP is 2-diphenylphosphino-5,6-dimethyl-7-phenyl-7-phosphabicyclo[2.2.1]hept-5-ene) compounds have been synthesized from [(η 6-arene)RuCl 2(DMPP)] (DMPP=3,4-dimethyl-1-phenylphosphole) and diphenylvinylphosphine (DPVP) in the presence of AgCF 3SO 3. The structures of 2, 3 and 4 were determined by X-ray crystallography. These complexes have been found to be quite effective catalysts for the transfer hydrogenation of ketones in 2-propanol in the presence of KOH.