| A substantial part of contemporary research focuses on renewable and alternative energy sources as well as the transformation of greenhouse gases into useful byproducts using unsaturated metal complexes. Of particular interest is the bond activation by metal complexes in which both the metal core and the ligand can play active and synergistic roles, thereby providing new catalytic opportunities. One class of ligands that can potentially play this active role are redox active ligands. Redox active ligands are defined as when the oxidation state of the metal becomes ambiguous due to the character of the ligand and the effect it has on the molecular orbitals within a complex.;A brand new redox-active pincer ligand synthesized by Dr. Kumar Parimal, is a 2,2',2"--terpyridine analog called bis(tetrazinyl)pyridine (bTzP). The novelty of bTzP lies in the tetrazinyl fragment's low lying LUMO (?*) combined with stable radical anions and unusually low reduction potentials, making it ideal for redox chemistry. The ligand has not one, but two tetrazinyl "arms", effectively increasing the number of electrons stored on the ligand. In effect, we envision this as a way to dramatically expand the number of possible redox states that a transition metal complex may sample during a catalytic cycle.;To understand the redox activity of the ligand, electrochemical studies were done on the bTzP ligand and a variety of bTzP-metal complexes. Specifically, the ligand was studied with transition metals at various oxidation states (Ni, Cu, V) to not only ascertain the coordination chemistry of the ligand but study the redox chemistry as well. Future work will focus on modifications to the ligand, future directions of synthesized metals, synthesis with early transition metals, and activation of small substrates. |
