Qiu Wei, Ren Fu-de, Shi Wen-jing, Wang Yan-hong
State Key Laboratory of Urban Water Resource and Enviroment, Harbin Institute of Technology, Harbin, 150001, China,
J Mol Model. 2015 May;21(5):114. doi: 10.1007/s00894-015-2653-x. Epub 2015 Apr 12.
As a follow-up to our investigation into the influence of H-bond on the C-NO2 trigger bond, a comparison of the effect of the H-bond on the ring strain energy with the C-NO2 bond dissociation energy was carried out in the HF complex with nitrocyclopropane, nitrocyclobutane, nitrocyclopentane, and nitrocyclohexane by using the DFT-B3LYP and MP2 (full) methods with the 6-311++G(2df,2p) and aug-cc-pVTZ basis sets. The C-NO2 bond length decreases with strengthening of trigger-bond while the ring perimeter increases companied by weakening of ring strain upon the complex formation. The H-bonding energy correlates well with the increment of ring perimeter and the change of ring bond angle. For nitrocyclopropane∙∙∙HF, the effect of H-bond on the ring strain energy is notable, while for the other complex, it is negligible. Therefore, for nitrocyclopropane∙∙∙HF, the origin of the change of explosive sensitivity might be due to the increment of the C-NO2 bond dissociation energy and decrease of the ring strain energy, while for the other complex, it might be only due to the strengthening of C-NO2 bond. The analysis of electron density shifts shows that the C-C bond in ring loses density while the C-NO2 bond gains density, leading to the weakened ring strain and strengthened C-NO2 bond, and thus the possibly reduced explosive sensitivity.
作为我们对氢键对C-NO₂触发键影响研究的后续，通过使用DFT-B3LYP和MP2（全）方法以及6-311++G(2df,2p)和aug-cc-pVTZ基组，对氢键在与硝基环丙烷、硝基环丁烷、硝基环戊烷和硝基环己烷形成的HF络合物中对环应变能和C-NO₂键解离能的影响进行了比较。随着触发键的增强，C-NO₂键长减小，而在形成络合物时，环周长增加，同时环应变减弱。氢键能与环周长的增加和环键角的变化密切相关。对于硝基环丙烷∙∙∙HF，氢键对环应变能的影响显著，而对于其他络合物，其影响可忽略不计。因此，对于硝基环丙烷∙∙∙HF，爆炸敏感性变化的起源可能是由于C-NO₂键解离能的增加和环应变能的降低，而对于其他络合物，可能仅由于C-NO₂键的增强。电子密度转移分析表明，环中的C-C键失去密度，而C-NO₂键获得密度，导致环应变减弱和C-NO₂键增强，从而可能降低爆炸敏感性。
