1-乙基-3-甲基咪唑四氟硼酸盐光谱分析与计算

Spectral Analysis and Calculations of 1-Ethyl-3-Methyl Imidazole Tetrafluoroborate

室温离子液体因其独特优良的理化性质备受关注,通过谱学和分子模拟、量化计算等方法相结合来研究离子液体的微观结构具有重要的意义。本文选取1-乙基-3-甲基咪唑四氟硼酸盐([EMIM][BF4)]作为研究对象,利用U4100分光光度计测量了[EMIM][BF4]在180～2 400 nm范围的光谱,对其在近紫外和近红外部分的振动吸收谱进行分析;并利用Gaussian 03W软件进行结构优化和振动频率计算得到红外光谱,进一步和实验图谱进行对比。结果发现,[EMIM][BF4]在近红外吸收谱是由咪唑环上两个取代基或C-H的倍频、合频、氢键产生的,而3C-7H键和F-B键对峰值大的红外吸收峰起着重要作用。

Room-temperature ionic liquids, particularly whose unique excellent physical and chemical properties, are being extensively studied for a variety of applications. Herein we selected the ionic liquids in common like 1-ethyl-3-methyl-imidazole tetrafluoroborate （ [ EMIM] [ BF41 ） as the research object. Using U4100 spectrophotometer, we measured the [ EMIM] [ BF4 ] ionic liquids in 180 - 2400 nm range of spectrum and analyzed especially infrared and near ultraviolet absorption spectrum of vibration. Then Gaussian 03W software of density functional （DFT） method is used for structure optimization and vibration frequency calculation. Further we compared and analyzed the experiment results and theoretical calculations in the infrared spectrum. The results showed that the near infra- red spectrum of [ EMIM ] [ BF4 ] may be caused by C-H bond, sum frequency,frequency multiplication or hydrogen bond, and 3C-7H, F-B bond plays an important role of the infrared absorption peaks.