Chelated [Zn(cyclam)]2+ Lewis acid improves the reactivity of the electrochemical reduction of CO2 by Mn catalysts with bulky bipyridine ligands.

This communication reports the use of a soluble Lewis acid complex, [Zn(cyclam)]2+ (cyclam = 1,4,8,11-tetraazacyclotetradecane) as a co-catalyst coupled with Mn(Mesbpy)(CO)3Br (Mesbpy = 6,6'-dimesityl-2,2'-bipyridine) for the electrochemical reduction of CO2 to CO. Utilization of the soluble chelated Lewis acid avoids the use of sacrificial additives and prevents the formation of insoluble products such as MgCO3 or ZnCO3 that change the thermodynamics of CO2 reduction. The use of soluble Lewis acids greatly improves catalysis compared to previously reported systems that used sacrificial anodes.