| The synthesis of Ru(acac)2X-bqdi (where X = 4-H, 4,5-CH3, 4-Cl, 4-NO2, N,N'-SO2 CH3) species is reported. The successful synthesis of these ruthenium complexes with the non-innocent benzoquinonediimine ligands was confirmed by NMR, MS and FT-IR data. The large degree of metal-to-ligand pi-backdonation observed for these complexes gives rise to unique properties which were analyzed through the use of electronic, electrochemical and spectroelectrochemical methods. The data are interpreted in the context of metal-ligand mixing and are supported by molecular-orbital composition computations using semi-empirical ZINDO and TD-DFT methods. Correlations between the substituents present on the quinoid ring, and the extent of pi-backdonation are also reported. |
