分子骨架异构对稠环含能化合物性能的影响: ICM-107与ANTTO的对比

To elucidate the influence mechanism of skeletal isomerism on the structure-property relationship of fused-ring energetic materials, a comparative study was conducted on two skeletal isomers, 3-amino-7-nitro-[1,2,4]triazolo[1,5-b][1,2,4,5]tetrazine-2-oxide(ICM-107)and 3,6-diamino-1,2,4-triazolo[4,3-b][1,2,4,5]tetrazine-7-oxide(ANTTO), focusing on their differences in energetic and safety performance. The intrinsic stability and reactivity of the molecules were evaluated using bond dissociation energy(BDE), energy gap(HOMO-LUMO), and electrostatic potential(ESP)analysis based on density functional theory(DFT). Molecular clusters extracted from crystal structures were further analyzed to characterize weak intermolecular interactions through interaction region indicator(IRI)analysis, Hirshfeld surface analysis, and 2D fingerprint plots. In addition, the sobEDAw method was employed to quantitatively calculate the decomposition of dimer interaction energies, while NICS and ICSS analyses were used to evaluate aromaticity characteristics. The results indicate that both compounds exhibit similar hydrogen bonding and van der Waals interactions, but ICM-107 shows higher molecular planarity. Therefore, the crystal packing efficiency(77.2%), density(1.973g/cm³)and detonation velocity(9584m/s)of ICM-107 are all superior to those of ANTTO(73.0%, 1.860g/cm³, and 9384m/s). The calculated BDEs(267.09kJ/mol and 265.10kJ/mol), HOMO-LUMO gaps(3.86eV and 3.91eV), and cluster binding energies of the two compounds show only minor differences, indicating comparable intrinsic stability and sensitivity. These findings demonstrate that skeletal isomerism has limited effect on intrinsic molecular stability, and primarily influences macroscopic energetic performance by modulating molecular planarity and thus affecting crystal packing. It is highlighted the critical role of molecular planarity in governing the energetic performance of fused-ring energetic materials.