Nitrogen-Rich Salts Based on the Energetic 5,5′-(Hydrazine-1,2-diyl)bis[1H-tetrazolide] Anion

The reaction of 5,5'-(hydrazine-1,2-diyl)bis[1H-tetrizole] (HBT) with N-bases yielded a new family of energetic N-rich salts based on the 5,5'-(hydrazine-1,2-diyl)bis[1H-tetrazol-1-ide] anion with ammonium (see 1), hydrazinium (see 2), guanidinium (see 3), and aminoguanidinium (see 4) cations (5,5'-(hydrazine-1,2-(diyl)bis[1H-tetrazol-1-ide]=5,5'-(hydrazine-1,2-diyl)bis[tetrazolate). All compounds were characterized by analytical and spectroscopic methods, and the crystal structure of 1 was determined by X-ray analysis (triclinic, P (1) over bar). (Carboxyamino)guanidine betaine monohydrate (=2(aminoiminomethyl)hydrazinecarboxylic acid hydrate (1:1); 5) was obtained as a by-product in the synthesis of 4 and was characterized by X-ray analysis (monoclinic, P2(1)/c). Differential-scanning calorimetric (DSC) measurements were used to assess the thermal behavior of the energetic salts 1-4, and bomb calorimetry allowed us to determine the experimental constant-volume energies of formation (Delta U-c(exp)). In addition, the detonation parameters (pressure and velocity) were calculated from the energies of formation (back-calculated from Delta U-c(exp)) with the EXPLO5 code, and their validity was checked by comparison with the results obtained from theoretical constant-volume energies of formation (Delta U-c(pred)) obtained by means of quantum-chemical calculation (MP2) of electronic energies and an approximation of lattice enthalpy. Lastly, the sensitivity to shock, friction, and electrostatic discharge of 1-4 was measured by submitting the compounds to standard tests, and the ICT code was used to predict the products formed upon decomposition of the salts.