Toward Advanced High-Performance Insensitive FOX-7-like Energetic Materials via Positional Isomerization

For an energetic molecule with a definite elemental composition, the substituent type and position are the most important factors to influence its detonation performance and mechanical sensitivities. In this work, two pairs of FOX-7-like energetic isomers based on (2 and HTz-FOX; 5 and 6) were synthesized and characterized. Through positional isomerization, advanced high-performance insensitive explosives were obtained. Compounds 2 and 5 with an amino group adjacent to the electron-withdrawing side of the ethene bridge show both higher thermal stability and lower mechanical sensitivities (2: T_d = 258 °C, impact sensitivity (IS) = 25 J, and friction sensitivity (FS) = 300 N; 5: T_d = 264 °C, IS = 30 J, and FS = 320 N). In addition, 2 shows ultrahigh detonation performance (D_v = 9224 m s^-1 and P = 31.1 GPa). These promising physicochemical properties are comparable to those of HMX (D_v = 9193 m s^-1, P = 37.8 GPa, T_d = 275 °C, IS = 7.4 J, and FS = 120 N), which suggests that 2 may be a promising energetic material in future applications.