Structural and theoretical studies of Xe(OChF(5))(2) and [XeOChF(5)][AsF6](Ch = Se, Te)

The XeOSeF5+ cation has been synthesized for the first time and characteriz ed in solution by F-19, Se-77 and Xe-129 NMR spectroscopy and in the solid state by X-ray crystallography and Raman spectroscopy with AsF6- as its cou nter anion. The X-ray crystal structures of the tellurium analogue and of t he Xe(OChF(5))(2) derivatives have also been determined: [XeOChF(5)][AsF6] crystallize in tetragonal systems, P4/n, a=6.1356(l) Angstrom, c = 13.8232( 2) Angstrom, V = 520.383(14) Angstrom (3), Z = 2 and R-1 = 0.0453 at -60 de greesC (Te) and a = 6.1195 (7) Angstrom, c = 13.0315 (2) Angstrom, V=488.01 (8) Angstrom (3), Z = 2 and R-1 = 0.0730 at -113 degreesC (Se); Xe(OTeF5)(2 ) crystallizes in a monoclinic system, P2(i)/c, a = 10.289(2) Angstrom, b=9 .605(2) Angstrom, c = 10.478(2) degrees, beta = 106.599(4)degrees, V = 992. 3(3) Angstrom (3), Z = 4 and R-i = 0.0680 at -127 degreesC; Xe(OSeF5)(2) cr ystallizes in a triclinic system, R (3) over bar, a = 8.3859(6) Angstrom, c = 12.0355(13) Angstrom, V = 732.98(11) Angstrom (3), Z = 3 and R-1 = 0.050 4 at -45 degreesC. The energy minimized geometries and vibrational frequenc ies of the XeOChF(5)(+) cations and Xe(OChF(5))(2) were calculated using de nsity functional theory, allowing for definitive assignments of their exper imental vibrational spectra. (C) 2001 Elsevier Science B.V. All rights rese rved.