Metalloligands containing aminofulvene-aldiminate (AFA) ligands and their bimetallic complexes.

A simple and convenient route to η(5)-coordinated Ru and Rh aminofulvene-aldiminate (AFA) complexes is described. The metalloligands [Cp*Ru{η(5)-(Ph(2)AFAH)}][BF(4)] (3), [Cp*Ru{η(5)-(benzyl(2)AFAH)}][OTf] (7), [Cp*Rh{η(5)-(Cy(2)AFA)H}][BF(4)](2) (8) and [Cp*Rh{η(5)-(Cy(2)AFA)}][BF(4)] (9) have been synthesised and characterised. The basicity of 9 has been found to be significantly less than its neutral analogue and thus eliminates the need for a deprotonation step to ligate to a second metal in the κ(2)-N,N'-coordination mode. The reaction of 9 with a palladium precursor provides a mixed-metal complex [Cp*Rh(η(5)/κ(2)-Cy(2)AFA)PdCl(2)][BF(4)] (12). Cyclic voltammetry studies of the Ph(2)AFAH ligand shows an irreversible one electron oxidation peak at +1.0 V (vs. Fc/Fc(+)). Complex 3 shows an irreversible oxidation at +1.5 V and a reduction peak at -1.0 V. The oxidation of 3 occurs on the AFA ligand backbone whereas the structurally analogous neutral 1,2-bis(imidoyl)pentamethyl-ruthenocene shows reversible oxidation at the Ru center.