Tuning energetic performance via isomerism: Trinitro 3,5-di(pyrazolyl)-1,2,4-oxadiazole isomers

A series of six isomers was synthesized with three nitro groups at various positions on the 3,5-di(pyrazolyl)-1,2,4-oxadiazole framework, providing a representative set for evaluating the effects of positional isomerism on physicochemical properties and performance. These isomers were thoroughly characterized by spectral data. X-ray crystallographic analysis of two isomers was also performed. The physicochemical properties of the isomers, such as density, thermal behavior, enthalpy of formation, and sensitivity towards impact and friction, were compared. The detonation properties were evaluated using the PILEM code. Based on physiochemical properties (density, thermal stability, and sensitivity) and the calculated detonation properties, compound 8 was found to have the best performance among the energetic isomers of this study.