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

摘要

simple and convenient route to η~5-coordinated Ru and Rh aminofulvene-aldiminate (AFA) complexes is described. The metalloligands [Cp~*Ru{η~5-(Ph_2AFAH)}][BF_4] (3), [Cp~*Ru{η~5-(benzyl_2AFAH)}][OTf] (7), [Cp~*Rh{η~5-(Cy_2AFA)H}][BF_4] _2 (8) and [Cp~*Rh{η~5-(Cy_2AFA)}] [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_2AFA)PdCl_2][BF _4] (12). Cyclic voltammetry studies of the Ph_2AFAH 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.