Bonding analysis of the effect of strain on trigger bonds in organic-cage energetic materials
Bonding analysis of the effect of strain on trigger bonds in organic-cage energetic materials
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DOI：
10.1007/s00214-020-02604-0
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发表时间：
2020-05
影响因子：
1.7
通讯作者：
C. A. Bayse;Mohammad Najib Jaffar
中科院分区：
文献类型：
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作者：
C. A. Bayse;Mohammad Najib Jaffar
维伯格键指数和自然键轨道分析用于检查应变对一系列有机笼分子触发键的影响。在取代的笼状烃中，内部 C-C 键的减弱和外部 C-X 键的增强是根据碳 2 和 2 原子轨道对键的贡献来解释的。硝基取代的四面体、棱柱石和立方烷中的内部 C-C 键（而不是 C-NO2 键）预计会断裂，引发爆炸性分解。笼分子中 C-C 键的活化随着硝基取代而增加，但全取代笼不一定是最活跃的。例如，预计七硝基立方烷比八硝基立方烷更敏感，这与实验研究一致。相比之下，对于一系列假设的硝基酯取代的棱柱石来说，外部 C-ONO2 键的强化比内部 C-C 键更能削弱 O-NO2 键。在 CL-20 和 TEX 中，通过 WBI 分析确定的稠合五元环和六元环笼形应变不如笼形碳氢化合物显着。在这些已知的高能材料中，N-NO2 触发键通过硝基的方向被激活。
Wiberg bond index and natural bond orbital analyses were used to examine the effect of strain on trigger bonds for a series of organic-cage molecules. In substituted cage hydrocarbons, weakening of the interior C–C bonds and strengthening of exterior C–X bonds are explained in terms of the contributions of the carbon 2sand 2patomic orbitals to the bonds. The interior C–C, rather than C–NO2, bonds are expected to break to initiate explosive decomposition in nitro-substituted tetrahedranes, prismanes, and cubanes. Activation of C–C bonds in cage molecules increases with nitro substitution, but persubstituted cages are not necessarily the most activated. For example, heptanitrocubane is predicted to be more sensitive than octanitrocubane, consistent with experimental studies. In contrast, for a series of hypothetical nitroester substituted prismanes, the strengthening of the exterior C–ONO2bond weakens the O–NO2bond more than the interior C–C bonds. In CL-20 and TEX, cage strain as determined by WBI analysis in the fused five- and six-membered rings is less significant than for the cage hydrocarbon. In these known energetic materials, the N–NO2trigger bonds are activated by the orientation of the nitro groups.