A new cocrystal explosive trinitrotoluene (TNT):1-amino-4-bromonaphthalene with reduced sensitivity

Authors: NİLGÜN ŞEN

Abstract: A 1:1 cocrystal of TNT and 1-amino-4-bromonaphthalene was prepared via solvent evaporation. The structure of the cocrystal was determined via single-crystal and powder X-ray diffraction. Crystal structure determination studies indicated that the main mechanism of cocrystallization originates from the intermolecular hydrogen bonding (amino-nitro), halogen bonding, and $\pi -\pi $ stacking. Investigation of intermolecular interactions by Hirshfeld surface and fingerprint plot analysis revealed that the structures were stabilized by H...H, O...H, C...C ($\pi -\pi )$ and Br...O interactions. Hirshfeld surfaces showed that these weak interactions were significant for crystal packing. We analyzed the crystal packing and showed how this may influence sensitivity to impact. The TNT:1-amino-4-bromonaphthalene cocrystal displays significantly reduced impact sensitivity relative to pure TNT, indicating for the first time that a new TNT cocrystal was less sensitive to impact than pure TNT component. This difference in impact sensitivities may arise from the considerably different intermolecular interactions seen in the cocrystal structure. The results highlight that cocrystallization is an effective way to alter the impact sensitivity, detonation performance, decomposition temperature, melting point, oxygen balance, crystal packing, and the density of explosives.

Keywords: Trinitrotoluene, sensitivity, cocrystal, insensitive energetic material

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