Thermal Stability Regulation of 1,3,4‐Oxadiazole‐Based Energetic Materials via Regioisomerism: Mechanism and Insights

The regioisomerism effect is a key strategy for regulating energetic materials properties, yet their intrinsic mechanisms remain to be thoroughly investigated. Employing density functional theory (DFT) calculations, this study systematically investigates the thermal stability control mechanisms of two sets of 1,3,4‐oxadiazole‐based regioisomeric energetic materials (Group a and b). By simulating the initial dissociation pathways, the decomposition processes are elucidated. Gibbs free energy calculations reveal that NO 2 dissociation constitutes the primary dissociation channel for all these isomers, with differences in dissociation energy barriers directly determining their thermal stability variations. Analysis of primary dissociation bond properties and intramolecular interactions evaluated the impact of the regioisomeric effect on molecular structure and primary dissociation bond strength. The study found that in thermally superior isomers, a stronger CNO 2 bond and the presence of intramolecular hydrogen bonding jointly stabilize the molecular structure; conversely, in isomers with inferior stability, the weak NNO 2 bond is the primary reason for their instability. These factors ultimately lead to significant differences in thermal stability between the isomers.