Generating Cu–Oxyl/Cu–Oxo Species from Cu–a-Ketocarboxylate Complexes and O2: In Silico Studies on Ligand Effects and C H-Activation Reactivity

The mechanistic details associated with the generation and reaction of [CuO]+ species from CuI-[alpha]-ketocarboxylate complexes, especially with respect to modifications of the ligand supporting the copper center, were investigated (see scheme). Theoretical models were used to characterize the electronic structures of different [CuO]+ species and their reactivity in C—H activation and O-atom transfer reactions.A mechanism for the oxygenation of CuI complexes with -ketocarboxylate ligands that is based on a combination of density functional theory and multireference second-order perturbation theory (CASSCF/CASPT2) calculations is elaborated. The reaction proceeds in a manner largely analogous to those of similar FeII-[alpha]-ketocarboxylate systems, that is, by initial attack of a coordinated oxygen molecule on a ketocarboxylate ligand with concomitant decarboxylation. Subsequently, two reactive intermediates may be generated, a Cu-peracid structure and a [CuO]+ species, both of which are capable of oxidizing a phenyl ring component of the supporting ligand. Hydroxylation by the [CuO]+ species is predicted to proceed [...] HUBER, Stefan M., et al. Generating CuII-Oxyl/CuIII-Oxo Species from CuIα-Ketocarboxylate Complexes and O2: In silico studies on ligand effects and C-H-activation reactivity. Chemistry A European Journal, 2009, vol. 15, no. 19, p. 4886-4895 DOI : 10.1002/chem.200802338