Strategy for Balance Energy and Safety: Salt Formation of Nitrogen-Rich Bicyclic Compounds Based on 1,2,4-Triazole

Nitrogen-rich heterocycles with high energy are ideal units for the design of energetic materials. An improved one-step reaction was carried out to obtain (tetrazolyl)-1,2,4-triazole 2 and (1,3,4-oxadiazolyl)-1,2,4-triazole 7. A series of energetic salts 3–5 and 9–11 were synthesized by treating 2 and 7 with the corresponding bases and acids, respectively. Single-crystal X-ray diffraction, elemental analysis, NMR spectroscopy, IR spectroscopy, synchronous thermal analysis, and a laser ignition system were used to characterize these synthesized compounds. All energetic salts expressed good stability (Td > 150 °C) and high nitrogen and oxygen content (N + O > 73.7%). Especially, hydrazinium salt 4 and dinitramide salt 11 exhibited good detonation velocities with the values of 9243 m s–1 and 8226 m s–1, respectively, which were higher than those of traditional insensitive explosive TATB (D = 8179 m s–1). Especially, 4 showed the best combustion performance. Salt formation contributes a simple and safe method to balance energy and safety in the field of energetic materials.