Balancing Energy and Stability: A Tetracyclic Bis(trinitromethyl)-Functionalized Triazole-Oxadiazole with High Density

Bis(trinitromethyl)oxadiazole compounds exhibit excellent detonation properties, but their thermal stability is poor, with a thermal decomposition temperature typically below 120 °C. To address this challenge, we designed a triazole linker synthesized via the cyclization of [3,3'-bi(1,2,4-oxadiazole)]-5,5'-dicarbohydrazide with ethyl 3-ethoxy-3-iminopropanoate to prevent direct linkage between the trinitromethyl groups and the 1,2,4-oxadiazole rings and thereby enhance the thermal stability of the compound. Using this strategy, a novel tetracyclic compound, 5,5'-bis(3-(trinitromethyl)-1H-1,2,4-triazol-5-yl)-3,3'-bi(1,2,4-oxadiazole) (TNTBO), was synthesized. TNTBO achieves a high density of 1.94 g cm⁻³, outstanding detonation performance (9261 m s⁻¹, P = 40.8 GPa) exceeding that of HMX (D = 9144 m s⁻¹, P = 39.2 GPa), and improved thermal stability with a decomposition temperature of 150 °C. This work presents a promising high-energy-density material and offers an effective molecular design approach for balancing energy output and thermal stability in this field.