Counter-Intuitive Gas-Phase Reactivities of [V ] and [V O] towards CO Reduction: Insight from Electronic Structure Calculations.

[V O] remains "invisible" in the thermal gas-phase reaction of bare [V ] with CO giving rise to [V O ] ; this is because the [V O] intermediate is being consumed more than 230 times faster than it is generated. However, the fleeting existence of [V O] and its involvement in the [V ] → [V O ] chemistry are demonstrated by a cross-over labeling experiment with a 1:1 mixture of C O /C O , generating the product ions [V O ] , [V O O] , and [V O ] in a 1:2:1 ratio. Density functional theory (DFT) calculations help to understand the remarkable and unexpected reactivity differences of [V ] versus [V O] towards CO .