Syntheses of [F₅TeNH₃][AsF₆], [F₅TeN(H)Xe][AsF₆], and F₅TeNF₂ and Characterization by Multi-NMR and Raman Spectroscopy and by Electronic Structure Calculations: The X-ray Crystal Structures of α- and β-F₅TeNH₂, [F₅TeNH₃][AsF₆], and [F₅TeN(H)Xe][AsF₆]

The salt, [F5TeN(H)Xe][AsF6], has been synthesized in the natural abundance and 99.5% 15N-enriched forms. The F5TeN(H)Xe+ cation has been obtained as the product of the reactions of [F5TeNH3][AsF6] with XeF2 (HF and BrF5 solvents) and F5TeNH2 with [XeF][AsF6] (HF solvent) and characterized in solution by 129Xe, 19F, 125Te, 1H, and 15N NMR spectroscopy at −60 to −30 °C. The orange [F5TeN(H)Xe][AsF6] and colorless [F5TeNH3][AsF6] salts were crystallized as a mixture from HF solvent at −35 °C and were characterized by Raman spectroscopy at −165 °C and by X-ray crystallography. The crystal structure of the low-temperature phase, α-F5TeNH2, was obtained by crystallization from liquid SO2 between −50 and −70 °C and is fully ordered. The high-temperature phase, β-F5TeNH2, was obtained by sublimation at room temperature and exhibits a 6-fold disorder. Decomposition of [F5TeN(H)Xe][AsF6] in the solid state was rapid above −30 °C. The decomposition of F5TeN(H)Xe+ in HF and BrF5 solution at −33 °C proceeded by fluorination at nitrogen to give F5TeNF2 and Xe gas. Electronic structure calculations at the Hartree−Fock and local density-functional theory levels were used to calculate the gas-phase geometries, charges, Mayer bond orders, and Mayer valencies of F5TeNH2, F5TeNH3+, F5TeN(H)Xe+, [F5TeN(H)Xe][AsF6], F5TeNF2, and F5TeN2- and to assign their experimental vibrational frequencies. The F5TeN(H)Xe+ and the ion pair, [F5TeN(H)Xe][AsF6], systems were also calculated at the MP2 and gradient-corrected (B3LYP) levels.