Xenon-Nitrogen chemistry: gas-phase generation and theoretical investigation of the xenon-difluoronitrenium ion F2N-Xe+.

The xenon–difluoronitrenium ion F2N[BOND]Xe+, a novel xenon–nitrogen species, was obtained in the gas phase by the nucleophilic displacement of HF from protonated NF3 by Xe. According to Møller–Plesset (MP2) and CCSD(T) theoretical calculations, the enthalpy and Gibbs energy changes (ΔH and ΔG) of this process are predicted to be −3 kcal mol−1. The conceivable alternative formation of the inserted isomers FN[BOND]XeF+ is instead endothermic by approximately 40–60 kcal mol−1 and is not attainable under the employed ion-trap mass spectrometric conditions. F2N[BOND]Xe+ is theoretically characterized as a weak electrostatic complex between NF2+ and Xe, with a Xe[BOND]N bond length of 2.4–2.5 Å, and a dissociation enthalpy and free energy into its constituting fragments of 15 and 8 kcal mol−1, respectively. F2N[BOND]Xe+ is more fragile than the xenon–nitrenium ions (FO2S)2NXe+, F5SN(H)Xe+, and F5TeN(H)Xe+ observed in the condensed phase, but it is still stable enough to be observed in the gas phase. Other otherwise elusive xenon–nitrogen species could be obtained under these experimental conditions.