Trifluorosulfite Anion, SOF₃^-

Abstract

Me4N+SOF3 -, the first example of a SOF3 - salt, has been prepared from Me4NF and SOF2. The colorless, microcrystalline solid was characterized by its Raman and infrared spectra, and in acetonitrile solution by 19F NMR. The structure of the SOF3 - anion is predicted by ab initio calculations to possess a pseudo trigonal bipyramidal structure with two remarkably long sulfur−fluorine bonds in the axial position. One fluorine, the oxygen atom, and a sterically active lone pair of electrons occupy the equatorial plane.

Fluoride ion transfer and stabilisation of reactive ions

“…Species with higher acceptor properties than the solvent will accept the fluoride. Very unusual inorganic ions have been generated by the method mainly in the laboratories of Christe, Seppelt and Schrobilgen (Scheme 6 [6,[46][47][48][49][50][51][52][53][54][55] …”

Synthesis and Characterization of Tetramethylammonium Trifluorosulfate

“…This indicates that the [SO 2 F 3 ] À anion undergoes a fast inter-or intramolecular ligand exchange, as was observed in the case of the [SOF 3 ] À anion. [16] To suppress a possible intermolecular exchange, a sample with an excess (ca. 50 %) of Me 4 NF was measured, but no significant changes occurred for the singlet at d = 79 ppm.…”

“…The oxygen atoms in the equatorial positions cause a bending of the F ax -S-F ax axis (165.28) and a compression of the F eq -S-O angle (115.48) from the ideal value of 1208. The S À O bond length of 143.2 pm is in the range of regular sulfur-oxygen double bonds in similar anions, such as SO 2 F À (calcd: 145.8 pm; exptl: 147.8(1) pm) [20,32] , SOF 3 À (calcd: 143.3 pm) [16] , and SO 3 F À (exptl: 142.4(4)-145.5 pm) [33] , and as expected longer than in SO 2 F 2 (138.6(2) pm), because the negative charge increases the ionic character of the bond. [34] The calculated S À F bonds of 168.5 and 157.9 are both longer than in SO 2 F 2 (151.4(2) pm) [34] and reveal the different kinds of bonds in the trigonal bipyramidal ion, which can be rationalized in terms of semi-ionic three-center fourelectron bonding for the axial fluorine ligands and a mainly covalent S À F eq bond.…”

“…Similar discrepancies were noted by us between Me 4 N + SOF 3 À and a reported Cs + SOF 3 À ion pair isolated in an argon matrix. [16] Another example is given by Christe et al who found large …”

Mean amplitudes of vibration of molecules and ions with interhalogen bonds and related species

“…In the case of F 3 ClO it is also interesting to make a comparison with the isoelectronic F 3 SO À anion [96]. As expected, the X O bond presents somewhat higher mean amplitude values in the anion, over the full temperature range and the same behavior is found for the X-F bonds at room temperature (for example, at 298.16 K, u S-O = 0.0366 Å , u S-F(ax) = 0.0519 Å , u S-(eq) = 0.0454 Å [25]).…”