Insight into the Thermostability and Low Sensitivity of Energetic Salts Based on Planar Fused-Triazole Cation

A new family of nitrogen-rich fused-triazole energetic salts based on 3,6-diamino-1H-[1,2,4]triazolo[4,3-b][1,2,4]triazole were synthesized and fully characterized by infrared spectroscopy (IR), 1H and 13C nuclear magnetic resonance, elemental analysis, differential scanning calorimetry (DSC). Structures of 3 and 4·H2O were confirmed by single-crystal X-ray diffraction analyses and their crystal packing characteristics were thoroughly analysed. All new compounds show good thermal stability (Td> 223°C) and tend to be insensitive to external mechanical stimulus. The densities of these salts ranged from 1.72 to 1.93 g cm-3. Theoretical performance calculations (Gaussian 09 and EXPLO 5) provided detonation pressures and velocities within the ranges of 20.8 to 32.9 GPa and 7599 to 8719 m s-1, respectively. The perchlorate salt 3 exhibits the highest density (1.93 g cm-3) and best oxygen balance (-30.0%), good thermal stability (Td = 258 °C), low sensitivities, and excellent detonation velocity (8719 m s-1) and pressure (32.9 GPa), which suggest that it has the potential to be used as High-energy-density material.