Pursuing Heat-Resistant and Insensitive Energetic Materials by Constructing Imino Bridged Conjugated Planar Structures

Developing insensitive heat-resistant energetic materials is currently a significant challenge in the research of energetic materials. In this study, two heat-resistant and insensitive energetic materials (compounds 3 and 4) were designed and prepared by constructing conjugated planar structure based on the imino bridged (−NH−) azoles and 5-chloro-3,6-dinitropyrazolo[1,5-a]pyrimidin-7-amine. All the newly synthesized compounds exhibit excellent thermal stabilities (T_d: 316.5–343.9 °C) and good detonation performances (D: 8183–8206 m s⁻¹), as well as satisfactory sensitivities (IS >40 J, FS >360 N). These remarkable stabilities are attributed to the π-conjugated planar structures and strong weak interactions in crystals. The comprehensive performances of compound 4 (T_d: 343.9 °C, D: 8183 m s⁻¹, IS >40 J, FS >360 N) are superior to those of the widely used heat-resistant explosive 2,2′,4,4′,6,6′-hexanitrostilbene (HNS) (T_d: 318 °C, D: 7612 m s⁻¹, IS: 5 J, FS: 240 N), indicating its potential to be used as heat-resistant and insensitive energetic materials.