A novel energetic framework with the combination of 5,6-fused triazolo-triazine and nitropyrazole-tetrazole for energy-stability balanced explosive

In recent years, the introduction of fused rings own high density and low sensitivity has promoted the development of energetic materials. However, the development of energetic compounds containing fused and bridged rings by introducing multiple nitrogen heterocycles at different sites of fused rings is still difficult to progress, which seriously limits the emergence of advanced energetic compounds. In this study, a series of energetic materials choosing different nitrogen rich heterocycles at the vacancies of the fused ring, i.e., neutral compound 5, 6 and their ionic derivatives (compounds 7–12) were designed and synthesized. Compounds 5 and 6 were further confirmed by single crystal X-ray diffraction, while the crystal analysis and theoretical calculations were carried out to explore the relationship between crystal structure and physicochemical properties. All of the newly synthesized compounds (5–12) are insensitive to mechanical stimulation (IS > 40 J; FS ≥ 342 N) and they own the high detonation velocity (D: 8322–9075 m/s). Notably, hydrazine salt 11 own the higher detonation velocity (9075 m/s) and powder density (1.83 g/cm3), but exhibits lower sensitivity (IS > 40 J) than the classical energetic compound RDX (8795 m/s, 1.80 g/cm3, 7.5 J). It is obvious that the combination of 5,6-fused triazolo-triazine and nitropyrazole-tetrazole may be a new energetic skeleton for synthesising the heterocyclic compounds with balanced energy-stability.