DFT Study on the Mechanism of the Activation and Cleavage of CO2 by (NHC)CuEPh3 (E = Si, Ge, Sn)

Density functional theory has been used to investigate the mechanism of the activation and cleavage of CO2 by the complexes (NHC)CuEPh3 (E = Si, Ge, Sn). Our results show that both the Cu-E and E-C(Ph) bonds are capable of activating and cleaving CO2. The reactivity of the Cu-E bond toward CO2 activation decreases as E becomes heavier, while the reactivity of the E-C(Ph) bond toward CO2 activation increases as E becomes heavier. The higher electron-releasing capability of (NHC)Cu compared to the, EPh3 group causes the EPh3 group to serve as a nucleophile (not an electrophile).