Pentafluorosulfanylnitramide Salts

Abstract

The synthesis and properties of a new class of inorganic salts, named pentafluorosulfanylnitramide salts (or pentafluorosulfanylnitraminic acid salts) [Z+SF5NNO2-], are described. A number of SF5-nitramide salts (Z+SF5NNO2-) were successfully prepared via nucleophilic displacements from carbamates and/or ion exchange techniques, but some salts [M(SF5NNO2)x; M = Li, Mg, Al] decomposed during isolation procedures and appear to be unstable in the solid state. Single-crystal X-ray diffraction was used to fully characterize the Z+SF5NNO2-, and their properties/structures are compared with those of the corresponding dinitramide salts (or dinitraminic acid salts), Z+N(NO2)2-. X-ray crystallography revealed major structural differences between N(NO2)2- and SF5N(NO2)- salts concerning the N-N distances and the angles subtended at the central nitrogen atom. In the N(NO2)2- salts, there are two nonequivalent N-N (average lengths 1.372(2) and 1.354(2) A) distances and an average N-N-N angle of 115.8(3) degrees (falls between sp3 and sp2 hybridization). In the SFsNNO2- salts, the average N-N distance is much shorter, 1.308(9) A, and the average N-N-S angle is 120.0(5) degrees (closely fits sp2 hybridization). The SF5NNO2- salts show a remarkable metrical similarity for the SF5 moiety in all structures, indicating a lack of sensitivity to its steric and electronic environment. This is in marked contrast to N(NO2)2-, where there is a wide variation in conformations adopted by these anions which can be related to their environment.

Pentafluorosulfanyl (SF5) Containing Energetic Salts

“…In sharp contrast, by simply elongating the alkyl chain in the SF 5 electrophile from ethyl to propyl, excellent yields resulted. For example, reaction of SF 5 CH 2 CH 2 CH 2 Br with N-methylimidazole (1) in a 1:1 molar ratio without solvent at 65°C for 12 h led to the formation of the quaternary salt 2 in 90 % isolated yield (Scheme 1).…”

“…Analogously, reactions of SF 5 CH 2 CH 2 CH 2 Br with 4-amino-1,2,4-triazole (3) and pyridine (5) gave the monoquaternary bromides 4 and 6 in Ͼ85 % isolated yields. Nitrate, perchlorate, dinitramide, and pentafluorosulfanylnitramide salts were synthesized by metathesis of the monoquaternary salts with silver nitrate, silver perchlorate, ammonium dinitramide, and potassium pentafluorosulfanylnitramide, [5] respectively, in aqueous solution (Scheme 1). Because some of the nitrate salts were hygroscopic, they were dried under vacuum for 24 h and stored in a desiccator for further analysis.…”

“…Washing of the crude products with an acetone/pentane mixture (1:3) gave 2, 4, and 6 in good yields. The nitrate, perchlorate, dinitramide and pentafluorosulfanylnitramide salts were synthesized by metathesis of the monoquaternary bromides with silver nitrate, silver perchlorate, ammonium dinitramide, and potassium pentafluorosulfanylnitramide [5] in water. Reactions of these bromides with silver salts in water in a 1:1 molar ratio were carried out at 25°C.…”

1,2,4‐Triazolium‐Cation‐Based Energetic Salts

“…The overall geometry of the anion is similar to that observed in comparable dinitramide salts. [60][61][62] The two NÀN bond lengths are approximately symmetric ( % 1.38 ) and shorter than a normal NÀN single bond (1.454 ), though longer than a N=N double bond (1.245 ). [47] The N-N-N angle is 115.1(2)8 as expected.…”

Synthesis and Characterization of 3,5‐Diamino‐1,2,4‐triazolium Dinitramide

“…[7] They often show excellent oxygen balances by combining both the fuel (tetrazole heterocycle) and the oxidizer (dinitramide). Many N-rich dinitramides like guanidinium dinitramide, [8] aminoguanidinium dinitromide, [9] bisguanidinium dinitramide [10] , guanylurea dinitramide (FOX-12) [11] and triaminoguanidinium dinitramide [4,12] were synthesized and characterized as energetic materials. Also tetrazolium derivatives, e.g.…”