离子液体[Bmim][BF_(4)]与氧化苯乙烯分子间相互作用及催化机理的和频振动光谱研究  

Unraveling Interactions and Catalytic Mechanisms of Ionic Liquid[Bmim][BF_(4)]and Styrene Oxide Using Sum Frequency Spectroscopy

作　　者：孟杜娟 韩琳玉 刘彩合 张悦凝 秦绪金 白羽[1] 郭源[1,2] 张贞 Dujuan Meng;Linyu Han;Caihe Liu;Yuening Zhang;Xujin Qin;Yu Bai;Yuan Guo;Zhen Zhang(Beijing National Laboratory for Molecular Sciences,CAS Research/Education Center for Excellence in Molecular Sciences,Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy Sciences,Beijing 100049,China)

机构地区：[1]中国科学院化学研究所,中国科学院分子科学科教融合卓越创新中心,北京分子科学国家研究中心,北京100190 [2]中国科学院大学,北京100049

出　　处：《Chinese Journal of Chemical Physics》2024年第2期420-428,I0088-I0098,I0105,共21页化学物理学报（英文）

基　　金：This work was supported by the National Natural Science Foundation of China(No.22173112);Chinese Academy of Sciences(No.YJKYYQ20180014).

摘　　要：离子液体作为多用途的反应介质和催化剂,在绿色化学和可持续化学领域引起了广泛的关注.本文采用和频产生振动光谱技术,深入研究了1-丁基-3-甲基咪唑四氟硼酸盐([Bmim][BF_(4)])与苯乙烯氧化物(SO)在空气/液体界面上的相互作用:在1000~3700cm^(-1)的光谱范围内,仅观察到了体系中碳氢键的振动模式.值得注意的是,研究发现苯乙烯氧化物的环氧环的取向是朝向体相的,而阳离子的咪唑环上的三个碳氢基则平行于界面表面,因此,在该体系中并未观察到阳离子与苯乙烯氧化物之间的相互作用.然而,在C-H键的振动谱中,发现CH(SO)和CH_(3)(阳离子)的振动光谱峰发生蓝移,这证明了阴离子BF4与环氧环上的CH_(2)基团之间存在相互作用,这种相互作用证实了离子液体首先催化苯乙烯氧化物并随后与CO_(2)反应的反应机制.本研究为反应界面的分子间相互作用和分子取向提供了重要的见解.The utilization of ionic liquids as versatile reaction media and catalysts has garnered significant attention in the field of green and sustainable chemistry.In this study,sum frequency generation vibrational spectroscopy(SFG-VS)is employed to investigate the interactions between 1-butyl-3-methylimidazolium tetrafluoroborate([Bmim][BF_(4)])and styrene oxide(SO)at the air/liquid interface.Spectral analysis in the range of 1000 cm^(−1) to 3700 cm^(−1) reveals that only vibrational modes of C–H bonds are observed.Notably,the orientation of the epoxy ring of SO is found to be towards the bulk phase,while the three C–H groups on the imidazolium ring of the cation are parallel to the surface.Consequently,there are no observed interactions between the cation and SO.However,in the vibrational spectra of C–H bonds,interactions between the anion BF4−and the CH_(2) group of the epoxy ring result in blue shifts in the vibrations of CH(SO)and CH_(3)(cation).These findings support a proposed reaction mechanism where the ionic liquid catalyzes SO first and subsequently reacts with CO_(2),providing valuable insights into intermolecular interactions and molecular orientations at reaction interfaces.

关 键 词：和频振动光谱 离子液体 分子间相互作用 催化机理 

分 类 号：Q241[生物学—细胞生物学]