Computational strategies to probe CH activation in dioxo-dicopper complexes

Abstract

We employ density functional theory and energy decomposition analysis to probe the mechanism of CH activation in dioxo-dicopper complexes. The electrophilicity of monodentate N-donor ligands coordinated to Cu is systematically varied to examine the response of barriers to the two proposed pathways – one-step oxo-insertion and two-step radical recombination. Electron-withdrawing ligand stabilize the oxo-insertion transition state via charge transfer interactions, and therefore lead to lower barriers. On the other hand, barriers to the CH activation step in the radical recombination mechanism exhibit almost no dependence on N-donor electrophilicity. Based on the similarities between calculated and experimental Hammett relationships, the oxo-insertion pathway appears to be the preferred mechanism of CH activation in dioxo-dicopper catalysts.