Halogen bonding (C-F···X) and its effect on creating ideal insensitive energetic materials

A series of 3-trifluoromethyl-6-amine-1,2,4-triazolo[4,3-b][1,2,4,5]tetrazine-based energetic materials were efficiency synthesized and fully characterized with IR, multinuclear NMR, and elemental analyses. All new compound structures were also confirmed via X-ray diffraction. Among them, compound 8 exhibits an excellent density of 1.90 g cm−3 which exceeds that of all currently reported trifluoromethyl-containing fused ring energetic materials. Additionally, it has good thermal stability (Td = 232 °C), excellent sensitivities (IS: > 60 J, FS > 360 N) and good detonation performance (Dv = 7877 m s−1, P = 26.8 GPa) which exceed the corresponding values of all reported trifluoromethyl-containing neutral energetic materials. Further, a detailed study based on X-ray diffraction, electrostatic potential, and intermolecular weak interactions in representative compounds and known compound III demonstrates that halogen bonding C-F···X plays an important role in creating good crystal stacking and reducing localized heating from external stimuli, which lead to insensitive energetic materials. This design method for next-generation energetic materials by incorporating intermolecular halogen bonding could be of future importance.