IR Spectroscopy of Gas Phase V(CO2) n + Clusters: Solvation-Induced Electron Transfer and Activation of CO2

Ion–molecule complexes of vanadium and CO2, i.e., V(CO2) n +, produced by laser vaporization are mass selected and studied with infrared laser photodissociation spectroscopy. Vibrational bands for the smaller clusters (n < 7) are consistent with CO2 ligands bound to the metal cation via electrostatic interactions and/or attaching as inert species in the second coordination sphere. All IR bands for these complexes are consistent with intact CO2 molecules weakly perturbed by cation binding. However, multiple new IR bands occur only in larger complexes (n ≥ 7), indicating the formation of an intracluster reaction product whose nominal mass is the same as that of V(CO2) n + complexes. Computational studies and the comparison of predicted spectra for different possible reaction products allow identification of an oxalate-type C2O4 anion species in the cluster. The activation of CO2 producing this product occurs via a solvation-induced metal→ligand electron transfer reaction.