XENO3- A GASEOUS CATION CHARACTERIZED BY A REMARKABLY STRONG XE-O BOND( )

The joint application of experimental techniques, such as MIKE, CAD, a nd FT-ICR spectrometry, and computational methods (DFT and QCISD(T)) h as allowed preparation and characterization of gaseous XeNO3+ and XeNO 2+ ions. The most stable structure of XeNO3+ has the XeONO2 connectivi ty, with a relatively short (2.088 Angstrom) Xe-O bond, and represents the gas-phase counterpart of Xe(II) nitrate, previously observed in s olution. The XeNO2+ cation is best characterized as a [Xe-NO2](+) comp lex, with a:large (3.018 Angstrom) Xe-NO2 separation and a relatively low dissociation energy, 10.8 kcal mol(-1). The reaction of XeNO3+ wit h selected nucleophiles, including CH3OH, C2H5NO2, CH3COCH3, CH3CN, an d C2H5CN, investigated by FT-ICR mass spectrometry, characterizes the ion as a nitrating agent. The unimolecular and collision-induced fragm entation of XeNO3+ and XeNO2+ is discussed.