Homo- and heterobimetallic complexes, in which half-sandwich complexes of ruthenium(II), rhodium(III), and iridium(III) are connected via three chloro bridges to RuCl2(PPh3)2, have been synthesized. The complexes were obtained in quant. yields by reaction of [(cymene)RuCl(m-Cl)]2 or [CpMCl(m-Cl)]2 (M = Rh, Ir) with [(PPh3)2ClRu(m-Cl)3Ru(Me2CO)(PPh3)2] (2). The crystal structure of 2 has been detd. by x-ray anal. Evidence that half-sandwich chloro complexes are generally suited for stabilizing RuCl2L2 fragments is provided by the synthesis of complexes [(cymene)Ru(m-Cl)3RuCl(dppb)] [dppb = 1,4-bis(diphenylphosphino)butane] and [(cymene)Ru(m-Cl)3RuCl(cod)] (cod = 1,5-cyclooctadiene), both of which have been structurally characterized. The abilities of all the complexes to catalyze the oxidn. of secondary alcs. with 2-butanone have been investigated. The complex [CpRh(m-Cl)3RuCl(PPh3)2] has proved to be highly active, displaying a performance superior to that of previously known catalysts such as [RuCl2(PPh3)3]. Using a substrate/catalyst ratio of 500:1, initial turnover frequencies of up to 3400 h-1 were obsd. The potential of these types of bimetallic complexes to act as catalysts for other reactions is discussed.
Paul Joseph Dyson, Lucinda Kate Batchelor
Vincent Kaufmann, Frédéric Kaplan, Guillaume Simon Joseph Drevon, Yann Francis Eric Dubois, Patrick Rerat, Nils Hamel
Nicolai Cramer, Coralie Danielle Annick Duchemin, Gints Smits