A 19F nuclear magnetic resonance investigation of the formation of Sb2F11− and SbnF5n+1− in the CsF–SbF5, t-butyl halide–SbF5, and tetraalkylammonium hexafluoroantimonate–SbF5 systems

Abstract

Fluorine nuclear magnetic resonance spectra have been obtained for the t-butyl fluoride–SbF₅, t-butyl chloride–SbF₅, tetraethylammonium hexafluoroantimonate–SbF₅, and cesium fluoride–SbF₅ systems, both with and without SO₂ solvent. In SO₂ solution the anion is Sb₂F₁₁⁻ for all the systems, any remaining SbF₅ being converted to SbF₅•SO₂. It is concluded that in the systems that do not contain SO₂, higher polymeric anions Sb_nF_5n+1⁻, where n > 2, are present. t-Butyl chloride and t-butyl fluoride give the t-butyl carbonium ion, as has been previously reported. Tetrabutylammonium and benzyltri-methylammonium cations appear to decompose to a carbonium ion and an adduct SbF₅•NR₃ in the presence of SbF₅.