Bond Dissociation Energy and Lewis Acidity of the Xenon Fluoride Cation

This study focuses upon the Lewis acid reactivity of XeF+ with various bases in the gas phase and the determination of the bond dissociation energy of XeF+. The bond dissociation energy of XeF+ has been measured by using energy-resolved collision-induced dissociation with neon, argon, and xenon target gases. Experiments with neon target yield a 298 K bond dissociation enthalpy of 2.81 ± 0.09 eV, and those with argon target give a similar value at 2.83 ± 0.12 eV. When using a xenon target, a significantly lower value of 1.95 ± 0.16 eV was observed, which corresponds closely with previous measurements and theoretical predictions. It is proposed that the lighter target gases give inefficient excitation of the XeF+ vibration leading to dissociation at energies higher than the BDE. Novel xenon-base adducts have been prepared in a flowing afterglow mass spectrometer by termolecular addition to XeF+ and by reaction of base with XeF+(H2O). New species have been characterized qualitatively by CID, and it is found that the products formed reflect the relative ionization energies of the fragments. Among the new xenon-containing species that have been prepared are the first examples of xenon carbonyls.