Multiple C-C bond formation upon electrocatalytic reduction of CO by an iron-based molecular macrocycle.

Molecular macrocycles are very promising electrocatalysts for the reduction of carbon dioxide into value-added chemicals. Up to now, most of these catalysts produced only C products. We report here that iron phthalocyanine, a commercially available molecule based on earth-abundant elements, can produce light hydrocarbons upon electrocatalytic reduction of CO in aqueous conditions and neutral pH. Under applied electrochemical potential, C to C saturated and unsaturated products are evolved. Isotopic labelling experiments unambiguously show that these products stem from CO. Control experiments and X-ray spectroscopic analysis show that the molecular catalyst remains intact during catalysis and is responsible for the reaction. On the basis of experiments with alternate substrates, a mechanism is proposed for the C-C bond formation step.