π-stacked interactions in explosive crystals:: Buffers against external mechanical stimuli
π-stacked interactions in explosive crystals:: Buffers against external mechanical stimuli
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DOI：
10.1021/ja800712e
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发表时间：
2008-07-02
影响因子：
15
通讯作者：
Huang, Hui
中科院分区：
文献类型：
--
作者：
Zhang, Chaoyang;Wang, Xiaochuan;Huang, Hui
讨论了一些爆炸晶体填料中π堆叠的相互作用。取一个典型的。以炸药2,4,6-三硝基苯-1,3,5-三胺（TATB）为样本，采用分子模拟方法，研究了炸药在外力刺激下可能发生滑动和压缩的pi-堆叠相互作用的性质。结果，在TATE的相邻层之间；在单位晶胞中，当TATB晶体顶层滑动时，静电吸引力随着vdW吸引力的减小而减小，而当TATB晶体沿c轴压缩时，vdW吸引力随着静电吸引力的减小而增大。同时，通过具有典型平面pi-堆叠结构的TATB、具有波浪状pi-堆叠结构的2,2-二硝基乙烯-1,1-二胺（福克斯-7）和不具有pi-堆叠结构的1,3,5,7-四硝基-1,3,5,7-四氮杂烷（HMX）三种代表材料，研究了pi-堆叠结构与炸药冲击灵敏度的相关性。结果表明，pi-堆叠结构，特别是平面层，可以有效缓冲外部机械刺激。即pi堆叠结构可以将作用在其上的机械能部分转化为分子间相互作用能，避免分子振动增大导致炸药分解，形成热点，最终引爆。这是π -叠炸药除了具有稳定的共轭分子结构外机械灵敏度低的另一个原因。
The pi-stacked interactions in some explosive crystal packing are discussed. Taking a typical. pi-stacked explosive 2,4,6-trinitrobenzene-1,3,5-triamine (TATB) as a sample and using molecular simulations, we investigated the nature of the pi-stacked interactions versus the external mechanical stimuli causing possible slide and compression of explosives. As a result, between the neighbor layers in the TATE; unit cell, the electrostatic attraction decreases with a little decrease of vdW attraction when its top layer slides, whereas the vdW attraction increases with a decrease of electrostatic attraction when TATB crystal is compressed along its c axis. Meanwhile, we studied the correlation between the pi-stacked structures and the impact sensitivities of explosives by means of three representatives including TATB with typical planar pi-stacked structures, 2,2-dinitroethylene-1,1-diamine (Fox-7) with wavelike pi-stacked structures, and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) without pi-stacked structure. The results showed that,pi-stacked structures, particularly planar layers, can effectively buffer against external mechanical stimuli. That is, pi-stacked structures can partly convert the mechanical energy acting on them into their intermolecular interaction energy, to avoid the increase of the molecular vibration resulting in the explosive decomposition, the formation of hot spots, and the final detonation. This is another reason for the low mechanical sensitivity of pi-stacked explosives besides their stable conjugated molecular structures.