Dinitrogen Activation in the Gas Phase: Spectroscopic Characterization of C-N Coupling in the V 3 C + +N 2 Reaction.

We report on cluster-mediated C-N bond formation in the gas phase using N 2 as a nitrogen source. The V 3 C + +N 2 reaction is studied by a combination of ion-trap mass spectrometry with infrared photodissociation (IRPD) spectroscopy and complemented by electronic structure calculations. The proposed reaction mechanism is spectroscopically validated by identifying the structures of the reactant and product ions. V 3 C + exhibits a pyramidal structure of C 1 -symmetry. N 2 activation is initiated by adsorption in an end-on fashion at a vanadium site, followed by spontaneous cleavage of the N≡N triple bond and subsequent C-N coupling. The IRPD spectrum of the metal nitride product [NV 3 (C=N)] + exhibits characteristic C=N double bond (1530 cm -1 ) and V-N single bond (770, 541 and 522 cm -1 ) stretching bands.