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.

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