On the Remarkable Role of the Nitrogen Ligand in the Gas-Phase Redox Reaction of the N2 O/CO Couple Catalyzed by [NbN].

The thermal gas-phase catalytic reduction of N2 O by CO, mediated by the transition-metal nitride cluster ion [NbN]+ , has been explored by using FT-ICR mass spectrometry and complemented by high-level quantum chemical calculations. In contrast to the [Nb]+ /[NbO]+ and [NbO]+ /[Nb(O)2 ]+ systems, in which the oxidation of [Nb]+ and [NbO]+ with N2 O is facile, but in which neither [NbO]+ nor [Nb(O)2 ]+ react with CO at room temperature, the [NbN]+ /[ONbN]+ system at ambient temperature mediates the catalytic oxidation of CO. The origins of the distinctly different reactivities upon nitrogen ligation are addressed by quantum chemical calculations.