Triazene-bridged energetic materials based on nitrotriazole: synthesis, characterization, and laser-ignited combustion performance

Compared to the widely concerned azo bridges (-NN-), triazene bridges (-NN-NH-) with longer nitrogen chains are also favorable linking units leading to novel energetic materials. In this work, a new family of nitrogen-rich nitrotriazolate-based energetic compounds with a triazene bridge were synthesized and well characterized. The experimental results indicated that most of these new compounds have good thermal stabilities and low sensitivities. Among these, ammonium 5,5'-dinitro-3,3'-triazene-1,2,4-triazolate (3) and potassium 5-nitro-3,3'-triazene-1,2,4-triazolate (7) decomposed at a relatively high temperature (240.6 °C for 3 and 286.9 °C for 7). The impact sensitivities of the obtained compounds ranged from 15 J to 45 J. They also have relatively high positive heats of formation between 667.5 to 817.3 kJ mol-1. The calculated detonation pressures (P) were located between 23.7 and 34.8 GPa, and the calculated detonation velocities (D) were between 8011 and 9044 m s-1. Interestingly, ammonium 5-nitro-3,3'-triazene-1,2,4-triazolate (8) and hydroxylammonium 5-nitro-3,3'-triazene-1,2,4-triazole (10) possessed excellent laser-ignited combustion performance.