Energetic derivatives of 3,3′,5,5′-tetranitro-4,4′-bipyrazole (TNBPz): Synthesis, characterization and properties

Abstract

3,3‘,5,5‘-Tetranitro-4,4‘-bipyrazole monohydrate (TNBPz, 1⋅H₂O) is an excellent precursor for the synthesis of new energetic materials (2–12). Several nitrogen-rich salts (e.g. guanidinium, aminoguanidinium, hydrazinium, ammonium and hydroxylammonium) were prepared from 1⋅H₂O by neutralization reactions. In addition, the N-methylation and N-amination of compound TNBPz was investigated and is reported. All new synthesized energetic materials were fully characterized by NMR (¹H, ¹³C, ¹⁴N, and ¹⁵N) spectroscopy, infrared spectroscopy, differential thermal analysis (DTA) and elemental analysis. Compounds 2, 4–8 and 10 were characterized with single crystal X-ray diffraction. The heats of formation for compounds 2, 4–6, 8, 11 and 12 were calculated using the atomization method based on CBS-4 M enthalpies. Several detonation parameters, such as detonation pressure, velocity and energy, were calculated by using the X-ray densities and the calculated standard molar enthalpies of formation. The sensitivities of all energetic materials toward external stimuli were tested according to the BAM standards. In addition, the toxicity toward vibrio fischeri bacteria of few energetic salts (3 and 4) is reported.