Exploiting the energetic potential of 1,2,4-oxadiazole derivatives: Combining the benefits of a 1,2,4-oxadiazole framework with various energetic functionalities

A series of 1,2,4-oxadiazole-derived energetic compounds were successfully synthesized using 1,2,4-oxadiazole-3-chloroxime as a versatile starting material. These energetic compounds were fully characterized by NMR spectroscopy, IR spectroscopy, and elemental analysis. The structures of compounds 5, 6a, 6c, 8 and 8a were determined by single crystal X-ray diffraction. The physicochemical and energetic properties of all the synthesized energetic compounds, including density, thermal stability and energetic performance (e.g., detonation velocities and detonation pressures) were investigated. Among these energetic compounds, hydrazinium salts 6b and 8b and hydroxylammonium salts 6c and 8c exhibit satisfactory calculated detonation performances, which outperform the commonly used high explosive RDX. Potassium salt 5 shows good detonation performance, high density as well as high sensitivity, making it a potential primary explosive. Compound 9 is a potential candidate for melt-cast explosives due to its remarkable liquid range between melting point (T_m = 98 °C) and decomposition temperature (T_d = 208 °C).