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Some new perfluoroalkyl derivatives of SeF4 and SeF6

1976; Elsevier BV; Volume: 7; Issue: 1-3 Linguagem: Inglês

10.1016/s0022-1139(00)84002-6

1873-3328

Clement Lau, Jack Passmore,

Fluorine in Organic Chemistry

(CF3)2SeF2 and (C2F52SeF2 are prepared by the reactions of the corresponding bis(perfluoroalkyl) monoselenide with chlorine monofluoride, and C2F5SeF3 by reacting bis(perfluoroethyl) diselenide with ClF. Trans C2F5SeClF4 is made by the reactions of either C2F5SeF3, CsF.C2F5SeF3, or (C2F5)2SeF2 with chlorine monofluoride, and C2F5SeF5 is produced by direct fluorination of CsF.C2F5SeF3. (C2F5)2SeF2 and C2F5SeF3 form the adducts (C2F5)2SeF2.AsF5 (or SbF5), C2F5SeF3.SbF5 and CsF.C2F5SeF3. The 19F n.m.r. and vibrational spectra of the neutral perfluoroalkly selenium(IV) derivatives have been recorded, and the results show their structures to be based on a trigonal bipyramid with the perfluoroalkyl group(s) preferentially occupying equatorial positions. The vibrational spectrum of CsF.C2F5SeF3 is consistent with an ionic formulation, and the spectra of the pentafluoride adducts suggest a substantial ionic contribution, with anion-cation interaction. The trans configuration of C2F5SeClF4 is consistent with its vibrational spectrum and is confirmed by the 19F n.m.r. study. The structure of C2F5SeF5 is deduced from its 19F n.m.r. spectrum.