Molecular conformation evolutions of trans HNS under high pressure.
Molecular conformation evolutions of trans HNS under high pressure.
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DOI：
10.1016/j.saa.2022.121994
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发表时间：
2022-10
期刊：
影响因子：
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通讯作者：
Chan Gao;Xiangdong Li;Junke Wang;Xiaoyu Sun;Shuang-Quan Liu;Zengming Zhang
中科院分区：
文献类型：
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作者：
Chan Gao;Xiangdong Li;Junke Wang;Xiaoyu Sun;Shuang-Quan Liu;Zengming Zhang
利用拉曼光谱和傅里叶变换红外光谱系统研究了高压下六硝基二苯乙烯（HNS）分子构象的变化。本文详细分析和阐明了常温下HNS与C-H、硝基、C双键C和环的振动模式，常温下trans-HNS关于-CH双键CH-对称分布，六个硝基对称分布。在1.4GPa和5GPa压力下，HNS的分子构象发生了两种变化，分别是由于环上C-H与N-O之间氢键相互作用的变化和反式烯烃的畸变引起的。在1.4GPa时，环上的C-H与N-O之间的氢键相互作用增强。它引起硝基的对称性简并和νas（NO2）、ν（C双键C）、ν（C-C）和ν（C-H）的拉曼变化。此外，HNS的非平面性和反式烯烃对压力的敏感性促进了反式烯烃的形变，以及在5GPa左右反式烯烃中C-H与N-O之间的氢键相互作用。当进一步加压时，C-H和N-O之间氢键相互作用的变化限制了C-H、NO2和环的振动。当压力超过5.7 GPa时，它阻断了非辐射途径，并激活了拉曼光谱中的强荧光背景。这些结果表明，HNS在高压下没有结构转变，只有构象变化。
The molecular conformation evolution of Hexanitrostilbene (HNS) under high pressure was systematically investigated using Raman and Fourier transform infrared (FTIR) spectroscopy. The vibration modes of HNS associated with C-H, nitro groups, Cdouble bondC and the ring have been analyzed and clarified in detail under ambient conditions.trans-HNS is symmetrically distributed about –CHdouble bondCH–, and six nitro groups are symmetrically distributed under ambient conditions. Two molecular conformation changes of HNS were observed at 1.4 GPa and 5 GPa due to the variations of hydrogen-bond interaction between C-H (in the ring) and N-O and the distortion oftransolefin, respectively. The hydrogen-bond interaction between C-H (in the ring) and N-O strengthened at 1.4 GPa. It induced the degenerated symmetry of the nitro groups and the Raman changes of νas(NO2), ν(Cdouble bondC), ν(C-C) and ν(C-H). In addition, the nonplanarity property of HNS and the sensitivity oftransolefin to pressure promoted the deformation oftransolefin, as well as the hydrogen bond interaction between C-H (intransolefin) and N-O at about 5 GPa. When further loading pressure on HNS, the variations in the hydrogen-bond interaction between C-H and N-O restricted the vibrations of C-H, NO2and the ring. It blocked the nonradiative pathway and activated the strong fluorescent background in the Raman spectra as the pressure increased above 5.7 GPa. These current results reveal that there is no structural transformation and only conformational changes under high pressure for HNS.