Xenon-Nitrogen Chemistry: Gas-Phase Generation and Theoretical Investigation of the Xenon-Difluoronitrenium Ion F2N-Xe+

The xenon-difluoronitrenium ion F2N-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 Moller-Plesset (MP2) and CCSD(T) theoretical calculations, the enthalpy and Gibbs energy changes (Delta H and Delta G) of this process are predicted to be -3 kcalmol(-1). The conceivable alternative formation of the inserted isomers FN-XeF+ is instead endothermic by approximately 40-60 kcalmol(-1) and is not attainable under the employed ion-trap mass spectrometric conditions. F2N-Xe+ is theoretically characterized as a weak electrostatic complex between NF2+ and Xe, with a Xe-N bond length of 2.4-2.5 angstrom, and a dissociation enthalpy and free energy into its constituting fragments of 15 and 8 kcal mol(-1), respectively. F2N-Xe+ is more fragile than the xenon-nitrenium ions (FO2S)(2)NXe+, 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.