title: Pincer and diamine Ru and Os diphosphane complexes as efficient catalysts for the dehydrogenation of alcohols to ketones.
abstract: The ruthenium and osmium complexes [MCl(2)(diphosphane)(L)] (M=Ru, Os; L=bidentate amino ligand) and [MCl(CNN)(dppb)] (CNN=pincer ligand; dppb=1,4-bis-(diphenylphosphino)butane), containing the N−H moiety, have been found to catalyze the acceptorless dehydrogenation of alcohols in tBuOH and in the presence of KOtBu. The compounds trans-[MCl(2)(dppf)(en)] (M=Ru 7, Os 13; dppf=1,1'-bisdiphenylphosphino)ferrocene; en=ethylenediamine) display very high activity and different substrates, including cyclic and linear alcohols, are efficiently oxidized to ketones by using 0.8-0.04 mol % of catalyst. The effect of the base and the comparison of the catalytic activity of the Ru versus Os complexes are reported. The ruthenium complex 7 generally leads to a faster conversion into ketones with respect to the osmium complex 13, which displays better activity in the dehydrogenation of 5-en-3β-hydroxy steroids. The synthesis of new Ru and Os complexes [MCl(2)(PP)(L)] (PP=dppb, dppf; L=(±)-trans-1,2-diaminocyclohexane,2-(aminomethyl)pyridine, and 2-aminoethanol) of trans and cis configuration is also reported.
authors.affiliation: Dipartimento di Scienze e Tecnologie Chimiche, Università di Udine, Via Cotonificio 108, 33100 Udine, Italy. inorg@uniud.it
authors.forename: Walter
authors.initials: W
authors.lastname: Baratta
authors.forename: Gianluca
authors.initials: G
authors.lastname: Bossi
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Putignano
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Rigo