Quaternary Salts Containing the Pentafluorosulfanyl (SF₅) Group

Abstract

The first quaternary salts of pyridine (2), N-methyl imidazole (3), N-propyl triazole (4), and pyridazine (5) that contain the pentafluorosulfanyl (SF(5)) group were prepared and characterized. Neat reactions of the aromatic nitrogen compounds with SF(5)(CF(2))(n)(CH(2))(m)I (n = 2 or 4, m = 2 or 4) gave quaternary iodides 6a-c, 7a-c, 8a, and 9a,b, which were metathesized with LiN(SO(2)CF(3))(2) to form the bis(trifluoromethylsulfonyl)amides 10a-c, 11a-c, 12a, and 13a,b, in high yields. With the exception of the pyridine bis(trifluoromethylsulfonyl)amide salts, the compounds melted or exhibited a T(g) at <0 degrees C. The methylimidazolium, pyridinium, and pyridazinium salts exhibited densities of approximately 2 g/cm(3). Particularly striking was the density of CF(3)(CF(2))(5)(CH(2))(2)-pyridazinium N(CF(3)SO(2))(2) measured at 2.13 g/cm(3); however, an atypically high density for the 1-CF(3)(CF(2))(5)(CH(2))(2)-3-methyl imidazolium amide (14) was also observed at 1.77 g/cm(3). All quaternary salts were characterized via IR, (19)F, (1)H, and (13)C NMR spectra and elemental analyses.

Pentafluorosulfanyl (SF5) Containing Energetic Salts

“…[7] A value of 1528.085 kJ mol -1 with correction of 6.197 kJ mol -1 was adopted for ∆H f o (H + , 298 K). [8,9] Heats of formation of HNO 3 and HN(NO 2 ) 2 in the gas phase are available (-32.1 and 29.9kcal/mol, respectively), [7] while the heat of formation of HClO 4 (g) is a little uncertain. In this work, 0.6 kcal mol -1 was used.…”

“…However, the G2 calculation gives 10.8 kcal/mol. Heats of formation of NO 3 -, ClO 4 -and N(NO 2 ) 2 -were calculated to be -73.6, -66.4, and -26.9 kcal/mol, respectively.…”

“…These values are similar to that of tetranitromethane (14.4 GPa). [13] 3 . Also, the pentafluorosulfanylnitramide derivative 4d has a melting point which is 71°C lower than 4b.…”

“…[3] Based on those results and the following observations: (1) indications that the SF 5 group can provide energetic salts with improved properties, i.e., increased density, decreased sensitivity and good thermal stability; and (2) the larger energy release found due to formation of HF in the detonation of SF 5 explosives [compare the average S-F bond energy (79 kcal/mol) to that of H-F (136 kcal/mol)], [4] we examined the impact of the pentafluorosulfanyl group on the properties of energetic salts. In the present work, we report the preparation and characterization of pentafluorosulfanylalkyl-substituted imidazolium, triazolium and pyridinium salts that contain highly oxidizing anions.…”

Synthetic chemistry and biological activity of pentafluorosulphanyl (SF5) organic molecules

“…Similarly, a series of quaternary trifluoromethanesulfonimide salts incorporating different Nheterocyclic residues were prepared by S N 2-reaction with the parent -iodo derivative followed by anion exchange (Scheme 51) [84]. Similar strategy was subsequently used to prepare energetic salts incorporating SF 5 -alkyl residues, heterocyclic rings and perchlorate, nitrate, and related counterions [85].…”