A Highly Efficient Molecular Iron(II) Photocatalyst for Concurrent CO2 Reduction and Organic Synthesis

Molecular catalysts used for photocatalytic reduction of CO2 heavily rely on photosensitizers to harvest light and then achieve photoinduced electron transfer to the catalytic center. However, a single earth-abundant molecular metal photocatalyst to independently execute CO2 reduction remains a huge challenge. Herein, we report that a polypyridyl iron(II) molecular photocatalyst 1, FePAbipyBn, exhibits outstanding activity for CO2 reduction in the presence of 1,3-diethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (TON 3558 for CO production and selectivity >99%). More strikingly, molecular photocatalyst 1 takes advantage of unique photoredox properties to concurrently facilitate 2e–/2H+ enamine oxidation and CO2 reduction, resulting in value-added products of indoles and CO. This is an inaugural instance of a photoredox reaction for CO2 reduction and organic synthesis using a molecular photocatalyst.