NHC‐Containing Manganese(I) Electrocatalysts for the Two‐Electron Reduction of CO 2

The synthesis and characterization of the first catalytic manganese N‐heterocyclic carbene complexes are reported: MnBr( N ‐methyl‐ N ′‐2‐pyridylbenzimidazol‐2‐ylidine)(CO) 3 and MnBr( N ‐methyl‐ N ′‐2‐pyridylimidazol‐2‐ylidine)(CO) 3 . Both new species mediate the reduction of CO 2 to CO following two‐electron reduction of the Mn I center, as observed with preparative scale electrolysis and verified with 13 CO 2 . The two‐electron reduction of these species occurs at a single potential, rather than in two sequential steps separated by hundreds of millivolts, as is the case for previously reported MnBr(2,2′‐bipyridine)(CO) 3 . Catalytic current enhancement is observed at voltages similar to MnBr(2,2′‐bipyridine)(CO) 3 .