Transition-metal complexes with redox-active, or ″non-innocent″, ligands have generated much interest in recent years. Ru-dioxolene complexes possess strong dp-pp metal-ligand interactions resulting in extensive delocalization of electron density which is very sensitive to the energies of the pp dioxolene orbitals. The charge distribution between the metal center and the ligand in these systems can be modulated depending on the nature of the ligand substituents. This charge distribution is often expressed in terms of resonance structures as dioxolene ligands can exist in quinone (Q), semiquinone (SQ) or catecholato (Cat) forms.¹ A number of Ru(OAc)(o-Iminosemiquinone)(tpy) complexes will be presented and their spectroscopic and electrochemical properties discussed (tpy = 2,2′:6′,2″-terpyridyl).

The research carried out at Brookhaven National Laboratory was supported under contract DE-AC02-98CH10886 with the U.S. Department of Energy.

1. Wada T.; Yamanaka M.; Fujihara T.; Miyazato Y.; Tanaka K. Inorg. Chem. 2006, 45, 8887.