An Efficient Strategy for Constructing Promising Heat-Resistant and Insensitive Energetic Materials Based on Imidazole and 1,3,4-Oxadiazole

A series of nitrogen heterocyclic imidazole-1,3,4-oxadiazole derivatives were synthesized to improve the thermal and mechanical stability of imidazole energetic materials. The relationship between the structure and property was investigated through the combination of theoretical calculations and experiments. All new synthesized compounds 4–9 exhibit low sensitivity (IS > 32 J, FS > 288 N). Furthermore, among all reported imidazole energetic compounds, the azo-linked compound (E)-1,2-bis(5-(4-nitro-1H-imidazol-2-yl)-1,3,4-oxadiazol-2-yl)diazene (5) has a more significant thermal decomposition temperature of 366 °C, higher than those of the famous heat-resistant energetic materials TATB (Td = 350 °C) and HNS (Td = 318 °C). The detonation velocity of compound 5 is 7872 m·s–1, which exceeds that of HNS (Dv = 7612 m·s–1). The results indicate that the azo-linked compound 5 has the potential to serve as a heat-resistant energetic material.