Preparation, Characterization, and Crystal Structures of the SO(3)NHF- and SO(3)NF(2)-Anions (PREPRINT)

摘要

Recently, a new class of high-energy-containing materials, gem- bis(difluoramino)-substituted heterocyclic nitramines, has gained attention as high-energy oxidizers: HNFX and TNFX have been successfully synthesized under strongly acidic conditions from their corresponding ketone derivatives using an excess of difluoramine. HNF2 is an unpredictably shock-sensitive and thermally unstable, gaseous compound which can be generated from different precursors, e.g., tetrafluorohydrazine, N,N-difluorourea, N,N-difluorocarbamates, or trityldifluoramine. Out of these precursors, only trityldifluoramine is a stable storable solid. However, it is not useful as a general reagent for the preparation of larger quantities of gem-bis(difluoramines) because its synthesis requires the use of expensive N2F4 which is commercially unavailable and must be prepared from difluoramine, and of equivalent amounts of mercury in an organic solvent. The use of mercury presents environmental problems, and working with N2F4 in an organic solvent can be hazardous. Therefore, it is highly desirable to develop a stable, solid, readily accessible difluoramine source. Obvious candidates for HNF2 sources were difluorosulfamate salts. Although the parent free acid, HOSO2NF2, had been known since 1961 and has been widely used as a difluoroaminating reagent, no reports could be found on the existence of its salts. In this paper, we report the results from two independent studies.