Oxygen-activating nickel(II) complexes

CHED 1206

Andrew M Lipchik, lipchikam@xavier.edu and Craig M Davis, davisc@xavier.edu. Department of Chemistry, Xavier University, 3800 Victory Parkway, Cincinnati, OH 45207-4221
Traditional oxidizing agents, such as hexavalent chromium, are costly and environmental hazards. A preferred oxidizing agent would be molecular oxygen, but the challenge is to develop catalysts which can activate molecular oxygen. Our group, in collaboration with Dr. Michael Baldwin of the University of Cincinnati, is devising nickel(II) catalysts to accomplish this goal. Nickel(II) is normally inactive towards oxygen activation due to the inaccessibility of its higher charge states, but the addition of electron-donating ligands lowers the oxidation potential. The Baldwin Group has observed that a Ni(II)-TRISOX complex can activate oxygen. Unfortunately, after ten turnovers the catalyst stops functioning. To circumvent this problem we have synthesized the bulkier TRITOX and TRIPHOX ligands. The synthesis and characterization of these new ligands and their Ni(II) complexes will be presented.