5-Amino-1H-1,2,4-triazole-3-carbohydrazide and its applications in the synthesis of energetic salts: a new strategy for constructing the nitrogen-rich cation based on the energetic moiety combination.

Nitrogen-rich cation 5-amino-1H-1,2,4-triazole-3-carbohydrazide and its derivatives were synthesized by a new molecular design strategy based on the energetic moiety combination. All derivatives were fully characterized by vibrational spectroscopy (IR), multinuclear (1H, 13C) NMR spectroscopy, elemental analysis, differential scanning calorimetry (DSC), and impact and friction-sensitivity tests. The structures of compounds 1-4, 7 and 8 were further confirmed by single-crystal X-ray diffraction and six different types of crystal packing were surprisingly discovered. The results show that the extensive hydrogen bonding interactions between the cations and anions lead to a complex 3D network, which contribute greatly to the high density, insensitivity and thermal stability of the 5-amino-1H-1,2,4-triazole-3-carbohydrazide salts. It is also found that the cationic form of 5-amino-1H-1,2,4-triazole-3-carbohydrazide can decrease the sensitivity and elevate the nitrogen content of the target salts effectively. Some of these salts exhibit reasonable physical properties, such as good thermal stability (up to 407 °C) and reasonable impact sensitivities (IS = 5-80 J). In addition, theoretical detonation properties of the energetic salts obtained with EXPLO 5 (version 6.02) confirm them as competitively energetic compounds comparable to those of RDX or HMX.