Energetic derivatives substituted with trinitrophenyl: improving the sensitivity of explosives

The incorporation of trinitrophenyl-modified 1,3,4-oxadiazole fragments is commonly observed in high-energy molecules with heat-resistant properties. This study explores the strategy of developing heat-resistant energetic materials by incorporating trinitrophenyl and an azo group into 1,3,4-oxadiazole, which involved the synthesis and characterization of (E)-1,2-bis(5-(2,4,6-trinitrophenyl)-1,3,4-oxadiazol-2-yl)diazene (2), N-(5-(2,4,6-trinitrophenyl)-1,3,4-oxadiazol-2-yl)nitramide (3), and the energetic salts of 3. Characterization techniques employed included ¹H and ¹³C NMR, IR and elemental analysis. Additionally, the structures of 2 and 3 were validated using single crystal X-ray analysis. To further understand the physical and chemical characteristics of these novel energetic compounds, various calculations and measurements were performed. Compound 2 exhibits excellent thermostability (T_d = 294 °C), which is comparable to that of traditional heat-resistant explosive HNS (T_d = 318 °C). But 2 is insensitive towards impact (>40 J) and friction (>360 N), surpassing HNS (5 J, 240 N), suggesting that compound 2 deserves further investigation as a potential heat-resistant explosive.