A RuII–N-heterocyclic carbene (NHC) complex from metal–metal singly bonded diruthenium(I) precursor: Synthesis, structure and catalytic evaluation

A mononuclear Ru(II)–N-heterocyclic carbene (NHC) complex [RuII(CO)2(κ2C,N-BIN)(H2O)Br][OTf] (OTf = trifluoromethane sulphonate) (1) has been synthesized in high-yield by the oxidative cleavage of the metal–metal singly-bonded diruthenium(I) precursor [Ru2(CO)4(CH3CN)6(OTf)2] with 1,8-naphthyridine functionalized NHC precursor 1-benzyl-3-(5,7-dimethyl-1,8-naphthyrid-2-yl)imidazolium bromide (BIN·HBr) at room temperature. Compound 1 catalyzes transfer hydrogenation of ketones to alcohols, and carbene-transfer from ethyl diazoacetate to a variety of substrates. It is shown to be an excellent catalyst for the insertion of carbene into the O–H and N–H bonds of alcohols and amines.