Pentafluoronitrosulfane, SF₅NO₂

Abstract

The synthesis of pentafluoronitrosulfane, SF5NO2, is accomplished either by reacting N(SF5)3 with NO2 or by the photolysis of a SF5Br/NO2 mixture using diazo lamps. The product is purified by treatment with CsF and repeated trap-to-trap condensation. The solid compound melts at -78 degrees C, and the extrapolated boiling point is 9 degrees C. SF5NO2 is characterized by 19F, 15N NMR, IR, Raman, and UV spectroscopy as well as by mass spectrometry. The molecular structure of SF5NO2 is determined by gas electron diffraction. The molecule possesses C2v symmetry with the NO2 group staggering the equatorial S-F bonds and an extremely long 1.903(7) Angstroms S-N bond. Calculated bond enthalpies depend strongly on the computational method: 159 (MP2/6-311G++(3df)) and 87 kJ mol(-1) (B3LYP/6-311++G(3df)). The experimental geometry and vibrational spectrum are reproduced reasonably well by quantum chemical calculations.

Preparation and Utility of Organic Pentafluorosulfanyl-Containing Compounds

“…Synthesis of 173 from SF 5 Br and NO 2 has also been attempted under photochemical conditions (Scheme ). Irradiation of SF 5 Br in an excess of NO 2 for 12 h afforded 173 in 3% yield …”

“…Preparation of 235a has also been accomplished by treating 236 with NaF pellets . Reaction of 237 with NO 2 at room temperature afforded very low yields of 173 , owing to decomposition of the product under the reaction conditions …”

“…174 Reaction of 237 with NO 2 at room temperature afforded very low yields of 173, owing to decomposition of the product under the reaction conditions. 137 N-Chloroamines containing the SF 5 group are useful synthetic intermediates for accessing other SF 5 -amine compounds through reaction of the chlorine atoms. Replacement of a chlorine atom with a hydrogen can be accomplished through reaction with water 31a or Hg/CF 3 CO 2 H (Scheme 64).…”

“…Irradiation of SF 5 Br in an excess of NO 2 for 12 h afforded 173 in 3% yield. 137 Only trace amounts of decomposition are observed at temperatures below 500 °C; above 500 °C, formation of SF 4 becomes more noticeable. A comparison of decomposition temperatures in closed vessels under pressure has shown that CF 3 SF 5 is more thermally stable than CF 3 CF 2 SF 5 ; the decomposition temperatures under these conditions were 423 and 380 °C, respectively.…”