Chelated [Zn(cyclam)]²⁺Lewis acid improves the reactivity of the electrochemical reduction of CO₂by Mn catalysts with bulky bipyridine ligands

Abstract

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.