1,3,4-Oxadiazole-Bridged 3,5-Dinitropyrazoles: Powerful Alliance toward High Performance and High Thermal Stability.

The ever-increasing demand for heat-resistant energetic materials in deep mining and space exploration has led to significant interest in developing new materials with exceptional thermal stability and detonation performance. In this work, a novel heat-resistant energetic compound, 2,5-bis(3,5-dinitro-1-pyrazol-4-yl)-1,3,4-oxadiazole (), was achieved through a simple and straightforward method where two 3,5-dinitropyrazole moieties are linked through a 1,3,4-oxadiazole ring. Compound , a symmetrical conjugated molecule, demonstrates superior thermal stability ( = 325 °C), good energetic performance ( = 8464 m s), and improved physical stability (IS = 7.5 J) compared to the industrially used heat-resistant explosive, HNS. The properties of were further optimized by forming energetic salts, and . An attempted reaction to synthesize zwitterionic compound , having 3,5-dinitropyrazole and 3,5-diamino-1,2,4-triazole ring connected via a C-C bond, resulted in another zwitterionic compound . Energetic salts ( = 291 °C) and ( = 275 °C), as well as zwitterionic compound ( = 286 °C), demonstrated excellent decomposition temperatures with good physical stability. The dihydroxylammonium salt () ( = 8507 m s, = 31.25 GPa) exhibited the best energetic properties, approaching the performance of RDX. The remarkable overall performance of compounds - makes them suitable candidates for high-performance, heat-resistant explosives.