Cyclometalation of Primary Benzyl Amines by Ruthenium(II), Rhodium(III), and Iridium(III) Complexes

Abstract

The cyclometalation of chiral and achiral primary amines occurred readily with Ru(II), Rh(III), and Ir(III) derivatives. Thus, the metalation of (R)-1-phenylethylamine by [(η6-benzene)RuCl2]2, [(η5-Cp*)RhCl2]2, and [(η5-Cp*)IrCl2]2 was studied. Good yields of the expected cationic products in which the phenyl group was ortho-metalated were obtained for the rhodium and the ruthenium derivatives, whereas a mixture of products was formed in the case of the iridium complex. Benzylamine, (R)-1-phenylpropylamine, (R)-1-(1-naphthyl)ethylamine, and (R)-1-aminotetraline afforded also the cycloruthenation products whose general formula is [(η6-benzene)Ru(N−C)(NCMe)]PF6 where N−C represents the ortho-metalated ligands. Substitution of the acetonitrile ligand by PMe2Ph occurred readily on the ruthenium complexes, affording stable compounds that were characterized by X-ray diffraction studies on single crystals, thus ascertaining the existence of the cycloruthenated five-membered rings. Accurate analyses of the struct...