Quantum chemical calculations based on 4,5-di(1,2,4-oxadiazol-3-yl)-2H-1,2,3-triazole and 3,3' -(2H-1,2,3-triazole-4,5-diyl)-bis(1,2,4-oxadiazol-5(4H)-one) derivatives: a DFT study.

context1,2,3-Triazole has excellent thermal stability, and both 1,2,3-triazole and 1,2,4-oxazolium are good in structural modifiability. This study employed density functional theory (DFT) to design 24 target compounds (designated PA-1 to PA-24) based on the characteristics of these two heterocyclic systems. Using 4,5-diallyl-2H-1,2,3-triazole-3,3'-(2H-1,2,3-triazole-4,5-diyl)-bis(1,2,4-oxadiazol-5(4H)-one) as the parent compound (labeled A1), we introduced different energetic substituents at the C3 position of the oxadiazole ring and the N2 position of the triazole ring. Alternatively, using 3,3'-(2H-1,2,3-triazole-4,5-diyl)-bis(1,2,4-oxadiazol-5(4H)-one) as the parent compound (labeled A2), we introduced different energetic substituents at the N2 position of the triazole ring. The selection process considered both macroscopic properties (heat of formation and detonation performance) and microscopic factors including frontier molecular orbitals, energy gaps, weak interactions, surface electrostatic potential, and bond parameters. This approach aimed to identify energetic materials with both detonation performance and safety characteristics while investigating how introducing different substituents at these two positions affects detonation performance and safety. The research results indicate the following: First, introducing an azide group at the C3 position of the oxadiazole in A1 more effectively enhances the compound's heat of formation. PA-13 (△H

methodAll calculations in this paper are based on density functional theory and were performed using the Gaussian16 software. Initially, the structures of PA-1 to PA-24 were optimized at the B3LYP-D3/6-311G** level. Subsequently, single-point energy calculations were conducted at the M06-2X-D3/def2-TZVPP level to determine the formation enthalpy, detonation velocity, and detonation pressure of the compounds. The Multiwfn and VMD programs were used to plot the energy gap diagrams, isosurface maps, scatter plots, and surface electrostatic potential maps for PA-1 to PA-24.