高等学校化学学报 ›› 2017, Vol. 38 ›› Issue (12): 2220.doi: 10.7503/cjcu20170390

• 物理化学 • 上一篇    下一篇

MnCl2/DMSO溶液的拉曼光谱和理论计算

吴晓静(), 刘阿钻   

  1. 合肥工业大学化学与化工学院, 合肥 230009
  • 收稿日期:2017-06-19 出版日期:2017-12-10 发布日期:2017-11-21
  • 作者简介:联系人简介: 吴晓静, 男, 博士, 副教授, 主要从事仪器分析研究. E-mail: wuxiaojing@ustc.edu

Studies of Raman Spectra and Theoretical Calculation of MnCl2/DMSO Solution

WU Xiaojing*(), LIU Azuan   

  1. School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009, China
  • Received:2017-06-19 Online:2017-12-10 Published:2017-11-21
  • Contact: WU Xiaojing E-mail:wuxiaojing@ustc.edu

摘要:

利用拉曼光谱研究了不同温度和浓度MnCl2/DMSO溶液体系离子的溶剂化作用, 结果表明, 在0~0.8 mol/L浓度范围内, 随着浓度增加, Mn2+与DMSO的相互作用逐渐增强, S=O伸缩振动峰向低波数移动, S=O双键减弱; C—S伸缩振动峰向高波数移动, C—S键增强. 温度升高, S=O双键和C—S键伸缩振动峰均向相反的方向移动, 溶剂化作用减弱. 56 ℃以上, 单体DMSO迅速增加, 与Mn2+溶剂化作用的DMSO迅速减少, 二聚体DMSO减少缓慢, 温度对溶剂化作用的影响大于溶剂自身的缔合. 利用密度泛函理论对可能存在的溶剂化构型[Mn(DMSO)n]2+进行了优化、 热力学性质及理论拉曼光谱计算, 从理论上证实了Mn2+与DMSO存在相互作用, 导致DMSO的S=O键拉伸和C—S键收缩, 与实验光谱结果一致.

关键词: 氯化锰/二甲基亚砜溶液, 拉曼光谱, 溶剂化作用, 溶剂化构型

Abstract:

The ion solvation of MnCl2/DMSO solutions was investigated by Raman spectra in different concentrations and temperatures. The results indicated that Mn2+ coordinated with DMSO molecules in the form of ions in the solutions, and the interaction gradually strengthened with the increase of concentrations between 0—0.8 mol/L. With the solvation of Mn2+ and DMSO molecules interaction increasing, S=O double peaks moved to low wave number, so S=O double bond weakened; C—S stretching vibration peak moved to high wave number, so C—S bond strengthened. Rising temperature, S=O double bond and C—S bond vibration peaks moved to the opposite direction, and the solvation effects gradually weaken. Above 56 ℃, monomer DMSO molecules rapidly increasing, DMSO molecules in the solvation sphere of the manganese cation rapidly reducing, dimer DMSO molecules slowly reducing, that illustrated that temperature had a greater influence on solvation effects than the association of solvent itself. Moreover the optimized possible solvation configuration [Mn(DMSO)n]2+, thermodynamic properties, and the theory of Raman spectra were calculated by density functional theory. The solvation of Mn2+ and DMSO molecules was confirmed by theory, which resulted in stretching of S=O bond and the contraction of C—S bond, consisting with the results of the experimental spectrum.

Key words: MnCl2/DMSO solution, Raman spectrum, Solvation, Solvation configuration

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