Bimetallic Cooperativity and Hydrogen Bonding Allow Efficient Reduction of CO2

Reducing CO2 selectively to one of the several C1 products is challenging, as the thermodynamic reduction potentials for the different n e(-)/n H+ reductions of CO2 are similar and so is the reduction potential for H+ reduction. Recently, Halime, Aukauloo, and co-workers have taken inspiration from the active site of nickel CO dehydrogenase (Ni-CODH) to design bimetallic iron porphyrins bridged by a urea moiety. These complexes show fast and selective reduction of CO2 to CO and the results suggest a Ni-CODH type mechanism at play where one of the two metals binds and reduces the CO2 while the other stabilizes the reduced species by forming a bridged complex, facilitating the C-O bond cleavage.

Automated summary

Reducing CO2 selectively to a specific C1 product is challenging due to similar thermodynamic reduction potentials for different CO2 reductions. Inspired by nickel CO dehydrogenase (Ni-CODH), the use of bimetallic iron porphyrins bridged by a urea moiety enables fast and selective reduction of CO2 to CO. The mechanism appears to mimic Ni-CODH, where one metal binds and reduces CO2 while the other stabilizes the reduced species and facilitates C-O bond cleavage.