Ligand Effects on the Reactivity of CuIL Complexes Towards Cl3CCO2−

The effect of the nature of the ligand L on the mechanism and kinetics of the reaction of CuIL with Cl3CCO2− in aqueous solution is reported. The results demonstrate that the rate of the chlorine abstraction reaction, which is usually the rate-determining step in the process, is affected by: a) the redox potential of the CuII/IL couple, b) the hybridization on CuI in the CuIL complex, c) steric hindrance, d) electron density on the central CuI cation, at the binding site of the chlorine atom to be abstracted. Measurement of ΔV≠ for the chlorine abstraction step indicates that this reaction proceeds by the inner-sphere mechanism, as expected. When the redox potential of the CuII/IL couple is considerably cathodically shifted the transient complex LCuII−CCl2CO2− is relatively long-lived.