Role‐Specialized Division of Labor in CO ₂ Reduction with Doubly‐Functionalized Iron Porphyrin Atropisomers

Abstract In enzymes, the active site residues function differently to promote chemical reactions. Such a role‐specialized division of labor has been rarely realized by synthetic catalysts. We report herein on catalytic CO 2 reduction with Fe porphyrins decorated with two cationic N,N,N ‐trimethylbenzylamine groups in cis ‐ or trans ‐arrangement. The cis ‐isomer outperforms the trans ‐isomer and reaches a TOF max of 4.4×10 5 s −1 in acetonitrile using phenol proton source. Theoretical studies revealed that the two cationic units in the cis ‐isomer are more effective than a single cationic unit to improve the CO 2 binding, and more importantly, they function differently but cooperatively to promote the C−O bond cleavage: one interacts with the CO 2 ‐adduct, while the other one interacts with the phenol molecule through electrostatic interactions. This work therefore presents a significant example of synthetic catalysts, which boost chemical reactions using a role‐specialized strategy for substrate activation.