Lewis Acids and Electron-Withdrawing Ligands Accelerate CO Coordination to Dinuclear Cu(I) Compounds

A series of dinuclear molecular copper complexes were prepared and used to model the binding and Lewis acid stabilization of CO in heterogeneous copper CO₂ reduction electrocatalysts. Experimental studies (including measurement of rate and equilibrium constants) and electronic structure calculations suggest that the key kinetic barrier for CO binding may be a σ-interaction between Cu(I) and the incoming CO ligand. The rate of CO coordination can be increased upon the addition of Lewis acids or electron-withdrawing substituents on the ligand backbone. Conversely, Keq for CO coordination can be increased by adding electron density to the metal centers of the compound, consistent with stronger π-backbonding. Finally, the electrochemically measured kinetic results were mapped onto an electrochemical zone diagram to illustrate how these system changes enabled access to each zone.

Johnsen, W. D.; Deegbey, M.; Grills, D. C.; Polyansky, D. E.; Goldberg, K. I.; Jakubikova, E.; Mallouk, T. E. Lewis Acids and Electron-Withdrawing Ligands Accelerate CO Coordination to Dinuclear Cu(I) Compounds Inorg. Chem. 2023, 62 (23) 9146-9157. https://doi.org/10.1021/acs.inorgchem.3c01003