Pentafluoroethyl Derivatives of Sulfur(IV) Fluorides and the Diazabicyclo[2.2.2]octane-SF4 Lewis-Acid-Base System
Lethbridge, Alta. : University of Lethbridge, Dept. of of Chemistry and Biochemistry
Pentafluoroethyl derivatives of sulfur(IV) fluorides were synthesized by reacting Me3SiC2F5 with SF4 and SOF2 forming SF3C2F5, SF2(C2F4)2, SOFC2F5, and SO(C2F5)2, all of which were modelled by B3LYP/aug-cc-PVTZ calculations and characterized by high-resolution fluorine-19 NMR spectroscopy including simulations of their complicated 19F NMR spectra. The X-ray crystal structures of SO(C2F5)2, Me3SiC2F5, and [S(OC2H5)3][H3F4] were determined, the latter being formed by the low-temperature alcoholysis of some sulfur(IV) species. The diazabicyclo[2.2.2]octane-SF4 Lewis acid-base system was investigated using Raman spectroscopy, including the formation of C6H12N2•2SF4 that was characterized by X-ray crystallography. When precipitated at low temperature, the DABCO-SF4 system incorporates additional non-adducted SF4 in the solid. Removing some SF4 under dynamic vacuum at –25 °C still left SF4 in the sample, presumably yielding the DABCO•SF4 adduct, based on Raman spectroscopy. The DABCO-SF4 system can be solvolysed by HF that is produced by the hydrolysis of SF4, forming crystals of [C6H12N2H]2F[SF5]•6SF4.
Lewis acids , Pentafluoroethyl derivatives , Sulfur(IV) Fluorides