Regulation of Crystal Packing and Energetic Performance of TNT Derivatives by Bromine Substitution

The development of high-density energetic materials requires precise control of molecular packing and intermolecular interactions within crystals. Herein, two brominated TNT derivatives, 3-BrTNT and 3,5-BrTNT, were synthesized and investigated to elucidate the effects of bromine substitution patterns on crystal structures and energetic properties. Single-crystal X-ray diffraction, electrostatic potential analysis and Hirshfeld surface analysis revealed that bromine substitution significantly regulates molecular packing and intermolecular interactions. Compared with 3-BrTNT, 3,5-BrTNT exhibits a higher crystal density of 2.312 g cm⁻³ and improved energetic performance, with calculated detonation velocity and pressure of 7915 m s⁻¹ and 31.86 GPa, respectively. These findings demonstrate that rational control of substituent arrangement provides an effective crystal engineering strategy for balancing energy output and safety in high-density energetic materials.