Imidazole-1,2,4-Oxadiazole Energetic Materials Functionalized with Carbonyl and Nitroamino Groups: Achieving High Performance and Low Sensitivity

To mitigate the inherent trade-off between energy and safety in 1,2,4-oxadiazole biheterocyclic energetic materials, the imidazole unit was incorporated into their framework to enhance stability. In this study, a series of insensitive (IS > 20 J, FS > 240 N) imidazole-1,2,4-oxadiazole energetic derivatives 6–10 and 12 with high energy (D_v: 7966–8995 m·s^–1) have been synthesized and further characterized. Among them, the nitroamino compound 8 exhibits the highest detonation performance (D_v = 8995 m·s^–1), higher than that of RDX (D_v = 8795 m·s^–1). Furthermore, compound 8 (IS = 25 J, FS = 240 N, T_d = 185 °C) also demonstrates insensitivity and high thermal stability, outperforming the currently reported 1,2,4-oxadiazole nitroamino compounds. The carbonyl compound 9 shows better overall performance. It has favorable safety characteristics, including low sensitivity (IS = 30 J, FS = 324 N) and a higher thermal decomposition temperature (T_d = 248 °C). Moreover, the detonation performance (D_v = 8396 m·s^–1) significantly exceeds that of TNT (D_v = 6881 m·s^–1). The results indicate that the imidazole-1,2,4-oxadiazole framework could serve as a promising candidate for constructing high-energy and insensitive energetic materials.