MnCl_2/DMSO溶液的拉曼光谱和理论计算

Studies of Raman Spectra and Theoretical Calculation of MnCl_2/DMSO Solution

利用拉曼光谱研究了不同温度和浓度MnCl_2/DMSO溶液体系离子的溶剂化作用,结果表明,在0~0.8mol/L浓度范围内,随着浓度增加,Mn^(2+)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Mn^(2+)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Mn^(2+)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.

The ion solvation of MnCl_2/DMSO solutions was investigated by Raman spectra in different concentrations and temperatures.The results indicated that Mn^（2＋） 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 Mn^（2＋） 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 Mn^（2＋） 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.