Synthesis and thermochemical properties of NF2-containing energetic salts

Ammonium, 1,5-diamino-4-methyl-tetrazolium and 4-amino-1-methyl-triazolium salts of 5-difluoroaminodifluoromethyl-tetrazolate (TA-CF2NF2) were prepared by metathesis reactions of silver 5-difluoroaminodifluoromethyl-tetrazolate and the corresponding iodides. All are thermally stable to ∼150 °C. The ammonium salt has a density of 1.88 g cm−3. The combination of the CBS-4 method and isodesmic bond separation reactions was found to be an economical and reliable method to estimate heats of formation for polyfluorinated molecules. The standard heats of formation ( Δ f H 298 ° ) of ammonium 5-difluoroaminodifluoromethyl-tetrazolate was calculated to be −53.13 kcal mol−1 using the CBS-4 method. While its detonation pressures (P) and velocities (D) were estimated using Cheetah 4.0: P = 28.78 GPa; D = 8490 m s−1; detonation properties for 1,5-diamino-4-methyl-tetrazolium salts of 5-difluoroaminomethyltetrazolate (TA-CH2NF2), 5-difluoroaminotetrazolate (TA-NF2) and 5-difluoroaminodinitromethyl-tetrazolate (TA-C(NO2)2NF2) are also compared based on predicted densities and computed heats of formation.