The Electrochemical Behavior of Early Metal Metallocene Cp2MCl2 Complexes under CO2
The electrochemical behaviors of seven early metal (groups 4–6) Cp2MCl2 species (M = Ti, Zr, Hf, V, Nb, Mo, and W; Cp = cyclopentadienyl) were examined under CO2 using cyclic voltammetry. In the presence of CO2, Cp2TiCl2, Cp2NbCl2, Cp2MoCl2 and Cp2WCl2 showed increases in current compared to an argon atmosphere at reductions corresponding to the formation of Cp2M species. The Cp2NbCl2 complex displayed the most current enhancement under CO2, but the electrochemical behavior was suppressed by the addition of excess water. The cyclic voltammograms of Cp2WCl2 displayed similar behavior in the presence of added water as the conditions under CO2 without added water. Bulk electrolysis of the Nb, Mo, and W species resulted in CO and H2 at low faradaic efficiencies. The geometries of the Cp2M and Cp2M(CO2) species were optimized using Density Functional Theory (DFT) to examine trends in reactivity.
Electrochimica Acta Volume 218, 10 November 2016, Pages 110-118