β-Oxochlorin cobalt(II) complexes catalyze the electrochemical reduction of CO2.

Inspired by the architecture of the macrocycle of heme d1, a series of synthetic mono-, di- and tri-β-oxo-substituted porphyrinoid cobalt(ii) complexes were evaluated as electrocatalytic CO2 reducers, identifying complexes of unusually high efficiencies in generating multi-electron reduction products, including CH4.