PNNL

Abstract

Recent studies from our laboratories have shown that the [Ni(PR2NR’¬2)2(CH3CN)]2+ complexes originally developed as artificial hydrogenases are also active electrocatalysts for formate oxidation (TOF ~16s-1). The focus of the current work is to develop a detailed understanding of the catalytic mechanism, which would aid in the design of improved CO2/formate interconversion catalysts. Based on electrochemical and spectroscopic experiments, including data for a new [Ni(PCy2NPhOMe2)¬2]2+ complex, we propose a mechanism in which the rate-determining step is a proton transfer from the Ni-O2CH ?-H to the ligand pendant base coupled with a 2e- transfer to Ni(II), circumventing direct hydride transfer to the metal center. Work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle.