Reduced State of Iridium PCP Pincer Complexes in Electrochemical CO2 Hydrogenation

We present a computational study on the mechanism for electrochemical reduction of CO2 using a PCP pincer iridium­(III) dihydride complex. Our results point toward a mechanism that involves an in situ-generated iridium­(I) hydride as the active species for the CO2 to formate reduction. The iridium­(III) path can operate in parallel but is associated with higher activation free energies in the reaction between the metal hydride and CO2, compared to the reaction at the in situ-generated iridium­(I) species.