Infrared spectroscopy of CO2 transformation by group III metal monoxide cations

Infrared photodissociation spectroscopy of mass-selected [MO(CO2)(n)](+) (M=Sc, Y, La) complexes indicates that the conversion from the solvated structure into carbonate one can be achieved by the ScO+ cation at n=5 and by the YO+ cation at n=4, while only the solvated structures are observed for the LaO+ cation. These findings suggest that both the ScO+ and YO+ cations are able to fix CO2 into carbonate. Quantum chemical calculations are performed on [MO(CO2)(n)](+) to identify the structures of the low-lying isomers and to assign the observed spectral features. Theoretical analyses show that the [YO(CO2)(n)](+) complex has the smallest barrier for the conversion from the solvated structure into carbonate one, while [LaO(CO2)(n)](+) exhibits the largest conversion barrier among the three metal oxide cations. The present system affords a model in clarifying the effect of different metals in catalytic CO2 transformation at the molecular level.