Imidazole for Pyridine Substitution Leads to Enhanced Activity Under Milder Conditions in Cobalt Water Oxidation Electrocatalysis

A previously
reported cobalt complex featuring a tetraimidazolyl-substituted
pyridine chelate is an active water oxidation electrocatalyst with
moderate overpotential at pH 7. While this complex decomposes rapidly
to a less-active species under electrocatalytic conditions, detailed
electrochemical studies support the agency of an initial molecular
catalyst. Cyclic voltammetry measurements confirm that the imidazolyl
donors result in a more electron-rich Co center when compared with
previous pyridine-based systems. The primary changes in electrocatalytic
behavior of the present case are enhanced activity at lower pH and
a marked dependence of catalytic activity on pH.