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Half‐Sandwich Chloro Complexes as Ligands for RuCl 2 L 2 (L = PR 3 , alkene): Syntheses, Structures, and Catalytic Activity of New Homo‐ and Heterobimetallic Complexes
Author(s) -
da Silva Ana C.,
Piotrowski Holger,
Mayer Peter,
Polborn Kurt,
Severin Kay
Publication year - 2001
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200103)2001:3<685::aid-ejic685>3.0.co;2-f
Subject(s) - chemistry , bimetallic strip , catalysis , rhodium , ruthenium , butane , iridium , medicinal chemistry , alkene , substrate (aquarium) , ligand (biochemistry) , stereochemistry , crystal structure , crystallography , organic chemistry , biochemistry , oceanography , receptor , geology
Homo‐ and heterobimetallic complexes, in which half‐sandwich complexes of ruthenium(II), rhodium(III), and iridium(III) are connected via three chloro bridges to RuCl 2 (PPh 3 ) 2 , have been synthesized. The complexes were obtained in quantitative yields by reaction of [(cymene)RuCl(μ‐Cl)] 2 or [Cp*MCl(μ‐Cl)] 2 (M = Rh, Ir) with [(PPh 3 ) 2 ClRu(μ‐Cl) 3 Ru(Me 2 CO)(PPh 3 ) 2 ] ( 2 ). The crystal structure of 2 has been determined by X‐ray analysis. Evidence that half‐sandwich chloro complexes are generally suited for stabilizing RuCl 2 L 2 fragments is provided by the synthesis of complexes [(cymene)Ru(μ‐Cl) 3 RuCl(dppb)] [dppb = 1,4‐bis(diphenylphosphanyl)butane] and [(cymene)Ru(μ‐Cl) 3 RuCl(cod)] (cod = 1,5‐cyclooctadiene), both of which have been structurally characterized. The abilities of all the complexes to catalyze the oxidation of secondary alcohols with 2‐butanone have been investigated. The complex [Cp*Rh(μ‐Cl) 3 RuCl(PPh 3 ) 2 ] has proved to be highly active, displaying a performance superior to that of previously known catalysts such as [RuCl 2 (PPh 3 ) 3 ]. Using a substrate/catalyst ratio of 500:1, initial turnover frequencies of up to 3400 h −1 were observed. The potential of these types of bimetallic complexes to act as catalysts for other reactions is discussed.