Structural and theoretical studies of Xe(OChF5)2 and [XeOChF5][AsF6] (Ch = Se, Te)

The XeOSeF5+ cation has been synthesized for the first time and characterized in solution by 19F, 77Se and 129Xe NMR spectroscopy and in the solid state by X-ray crystallography and Raman spectroscopy with AsF6− as its counter anion. The X-ray crystal structures of the tellurium analogue and of the Xe(OChF5)2 derivatives have also been determined: [XeOChF5][AsF6] crystallize in tetragonal systems, P4/n, a=6.1356(1) Å, c=13.8232(2) Å, V=520.383(14) Å3, Z=2 and R1=0.0453 at −60°C (Te) and a=6.1195(7) Å, c=13.0315(2) Å, V=488.01(8) Å3, Z=2 and R1=0.0730 at −113°C (Se); Xe(OTeF5)2 crystallizes in a monoclinic system, P21/c, a=10.289(2) Å, b=9.605(2) Å, c=10.478(2) Å, β=106.599(4)°, V=992.3(3) Å3, Z=4 and R1=0.0680 at −127°C; Xe(OSeF5)2 crystallizes in a triclinic system, R3̄, a=8.3859(6) Å, c=12.0355(13) Å, V=732.98(11) Å3, Z=3 and R1=0.0504 at −45°C. The energy minimized geometries and vibrational frequencies of the XeOChF5+ cations and Xe(OChF5)2 were calculated using density functional theory, allowing for definitive assignments of their experimental vibrational spectra.