Light driven metal pincer photocatalysts for carbon dioxide reduction to carbon monoxide

A compound having Formula I

• wherein,
• R1 is OH, O−, halogen, amine, —O-alkyl, —O-alkenyl, alkynyl, —O-aryl, —O-heteroaryl, —O-benzyl, O-cycloalkyl, or —O-cycloalkenyl, wherein R1 is optionally substituted with alkyl, alkoxy, alkenyl, alkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, thiol, phosphonyl, or photosensitizer;
• each R2 is, independent of the other, alkyl, alkenyl, alkynyl, aryl, or heteroaryl, wherein R2 is optionally substituted with alkyl, alkoxy, alkenyl, alkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, or thiol;
• each R3 and R4 are, independent of the other, hydrogen, alkyl, alkenyl, alkynyl, aryl, or heteroaryl, wherein R3 and R4 are optionally substituted with alkyl, alkoxy, alkenyl, alkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, or thiol, or R3 and R4 combine together with the atoms to which they are attached to form a cycloalkyl, cycloheteroaryl, aryl, or heteroaryl;
• M is Ni, Ru, Fe, Co, or Ir;
• each L is independently chosen from Cl, Br, CH3CN, DMF, H2O, bipyridine, phenylpyridine, CO2, and a CNC-pincer ligand;
• and
• n is 1, 2, or 3.