Gas-phase reactivity of selected transition metal cations with CO and CO2 and the formation of metal dications using a sputter ion source

Reaction products and rates were measured for the gas-phase reactions of selected first row transition metal ions (Ti+, V+, Fe+, Co+, Ni+, Cu+, Zn+) and both CO and CO2 using a flowing afterglow instrument. The formation and description of products formed and reaction mechanisms are presented and discussed as well. Ab initio calculations were used to produce potential-energy surface diagrams for selected reactions as a tool to further understand the reaction mechanisms, thermochemistry, and reaction kinetics. Reactions with CO are slow and typically yield complexes of the form M(CO)(n)(+) (n = 1-2), with the second CO molecule appearing to be added faster than the first one. Reactions with CO2 also yield the formation of clusters; however, in the case of Ti+, the reaction produces the oxide TiO+ ion efficiently. An interesting observation was also the formation of metal doubly charged ions. Some dications were easily obtained as the major ion by changing the ionization conditions in the sputter ion source. We are proposing an ionization mechanism for the formation of the dications.