Xenon(IV)–Carbon Bond of [C6F5XeF2]+; Structural Characterization and Bonding of [C6F5XeF2][BF4], [C6F5XeF2][BF4]·2HF, and [C6F5XeF2][BF4]·nNCCH 3 (n = 1, 2); and the Fluorinating Properties of [C6F5XeF2][BF4] Academic Article uri icon

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abstract

  • The [C6F5XeF2](+) cation is the only example of a Xe(IV)-C bond, which had only been previously characterized as its [BF4](-) salt in solution by multi-NMR spectroscopy. The [BF4](-) salt and its new CH3CN and HF solvates, [C6F5XeF2][BF4]·1.5CH3CN and [C6F5XeF2][BF4]·2HF, have now been synthesized and fully characterized in the solid state by low-temperature, single-crystal X-ray diffraction and Raman spectroscopy. Crystalline [C6F5XeF2][BF4] and [C6F5XeF2][BF4]·1.5CH3CN were obtained from CH3CN/CH2Cl2 solvent mixtures, and [C6F5XeF2][BF4]·2HF was obtained from anhydrous HF (aHF), where [C6F5XeF2][BF4]·1.5CH3CN is comprised of an equimolar mixture of [C6F5XeF2][BF4]·CH3CN and [C6F5XeF2][BF4]·2CH3CN. The crystal structures show that the [C6F5XeF2](+) cation has two short contacts with the F atoms of [BF4](-) or with the F or N atoms of the solvent molecules, HF and CH3CN. The low-temperature solid-state Raman spectra of [C6F5XeF2][BF4] and C6F5IF2 were assigned with the aid of quantum-chemical calculations. The bonding in [C6F5XeF2](+), C6F5IF2, [C6F5XeF2][BF4], [C6F5XeF2][BF4]·CH3CN, [C6F5XeF2][BF4]·2CH3CN, and [C6F5XeF2][BF4]·2HF was assessed with the aid of natural bond orbital analyses and molecular orbital calculations. The (129)Xe, (19)F, and (11)B NMR spectra of [C6F5XeF2][BF4] in aHF are reported and compared with the (19)F NMR spectrum of C6F5IF2, and all previously unreported J((129)Xe-(19)F) and J((19)F-(19)F) couplings were determined. The long-term solution stabilities of [C6F5XeF2][BF4] were investigated by (19)F NMR spectroscopy and the oxidative fluorinating properties of [C6F5XeF2][BF4] were demonstrated by studies of its reactivity with K[C6F5BF3], Pn(C6F5)3 (Pn = P, As, or Bi), and C6F5X (X = Br or I).

authors

  • Koppe, Karsten
  • Haner, Jamie
  • Mercier, Hélène PA
  • Frohn, Hermann-J
  • Schrobilgen, Gary

publication date

  • November 3, 2014