Azo1,3,4-oxadiazole as a Novel Building Block to Design High-Performance Energetic Materials

In this study, the azo1,3,4-oxadiazole energetic fragment was first introduced into the energetic materials using a simple synthetic strategy, yielding two symmetrical covalent compounds 4 and 5. All new compounds (3-5) were well-characterized by IR spectroscopy, NMR spectroscopy, thermal analysis, and single-crystal X-ray diffraction analysis. As supported by differenctial scanning calorimetry data, compounds 4 and 5 possess excellent decomposition temperatures as high as 248 and 278 degrees C, respectively. To the best of our knowledge, 278 degrees C ranks highest in all 1,3,4-oxadiazole-based energetic compounds. Their energetic performances were evaluated with EXPLO5. Both 4 and 5 show good detonation velocities (D) of 8409 and 8800 m s(-1) and detonation pressures (P) of 29.3 and 35.1 GPa, comparable to RDX (D: 8795 m s(-1), P: 34.9 GPa). Furthermore, on the basis of the single-crystal data, quantum-chemical calculations were employed to better understand their intrinsic structure-property relationship. All these positive results indicate the superior potential of the azo1,3,4-oxadiazole backbone for designing next generation of energetic materials.