Enhancing the detonation performance of azobistriazole energetic derivatives via inducing N-oxide groups

Abstract

The N-oxide strategy plays a crucial role in regulating the performance and safety of energetic materials. This study mainly addresses the question of how the N-oxide group affects the properties of azobistriazole and its derivatives. Our findings indicate that the N-oxide group can increase the density of the system, and its effect on the enthalpy of formation depends on the specific situation. The N-oxide groups can effectively improve the density and energetic properties. Some of the energetic derivatives containing N-oxide groups have a density as high as 2.097 g cm⁻³ (D3–NO(2)) and a detonation velocity as high as 10 275 m s⁻¹ (C6–NO(2)). The effect of N-oxide groups on the enthalpy of formation depends on the specific circumstances. The effect of N-oxide groups on the stability of azobistriazole energetic derivatives is relatively complex. Among them, the N-oxide group on the triazole ring has an opposite effect on the bond dissociation enthalpy of functional groups. When the N-oxide group is on the 1,2,3-triazole ring, it can improve C–R (R is equal to C(NO₂)₃, NF₂, NHNO₂, NO₂, and ONO₂ respectively) bond dissociation enthalpy, and when it is on the 1,2,4-triazole ring, it will reduce the C–R bond dissociation enthalpy. When the N-oxide group is located on the azo bond, the bond dissociation enthalpy of the azo bond will be significantly reduced. This article systematically explores the effect of N-oxide groups on the properties of azobistriazole energetic derivatives, which will help people better utilize N-oxide groups to design and synthesize new energetic materials.