Organometallic aqua ions of the transition metals

Abstract

A state-of-the-art report on Organometallic water complexes of the general composition [L πM(H 2O) n ] n+ , where L π is a carbon π ligand, arene, cyclopentadienyl (pentamethylcyclopentadienyl, Cp *) or olefin. Systems studied to date are [Cp 2( *)Ti(H 2O) 2] 2+, [Cp( *)Cr(H 2O) 3] 2+, [Cp *Co(Rh,Ir)(H 2O) 3] 2+, [(arene)Ru(Os)(H 2O) 3] 2+, [(TMT)Ru(H 2O) 3] 2+ (TMT = tetramethylthiophene), [(COD, NBD)Ru(H 2O) 4] 2+ (COD = 1,5-cyclooctadiene; NBD = norbornadiene), [(CO)Ru(H 2O) 5] 2+, [(C 4R 4)M(H 2O) 3] 2+ (M = Ni, Pd, Pt) as well as some olefin aqua complexes of Rh(I). In many of these systems, the tripodal oxygen ligand [CpCo{PO(OR) 2} 3] − can serve as a model for three coordinated water molecules, where tripod complexes are stabilized in comparison with analogous water complexes. Structural, electrochemical and kinetic parameters of water exchange are discussed.