Fluorine introduction into asymmetric energetic systems: balancing thermal stability and detonation performance

In recent years, the modification of gem-dinitro and trinitromethyl-based energetic materials has attracted considerable attention. This study summarizes recent strategies for improving material performance by introducing fluorine atoms into asymmetric gem-polynitro structures. It was found that the introduction of fluorine atoms effectively increases the thermal stability and density of these materials while maintaining their detonation performance. Frontier molecular orbital (FMO) analysis reveals that the incorporation of fluorine atoms enlarges the HOMO-LUMO gap, thereby enhancing molecular stability. Furthermore, atomic dipole moment corrected Hirshfeld (ADCH) atomic charge and electrostatic potential (ESP) analyses indicate that introducing fluorine into the parent asymmetric gem-dinitro/trinitromethyl energetic materials effectively enhances thermal stability by promoting a more uniform charge distribution across the system. Finally, based on the known experimental structure 5, a novel compound (5-F) was designed. Computational results demonstrate that both the detonation velocity and density of compound 5-F are significantly improved. This research strategy provides valuable guidance for the design and synthesis of next-generation gem-polynitro energetic materials.

All calculations were performed using Gaussian 16 software and the Multiwfn program package, and the Grimme dispersion correction was employed in the present work. Specifically, the M06-2X functional combined with the def2-TZVP basis set was used for molecular structure (1-4) optimization and frequency calculation; the B3PW91 functional and 6-31G** basis set were adopted for density calculation (5-F); the B3LYP functional and 6-31G** basis set were utilized for structural optimization in enthalpy of formation calculation, while the single-point energy was calculated at the M06-2X/def2-TZVP level (5-F).