研究了不同浓度下二甲基亚砜(D M S O)水溶液混合的拉曼光谱特性变化.随着水浓度的增加,S=O基团在1017 cm-1处出现新的振动峰且强度不断增强,1029 cm-1的反对称伸缩振动受到了抑制.此外,与C-S-C基团和CH3基团的蓝移相比,S=O基团呈现出相反的红移趋势.采用量子化学计算密度泛函理论研究了DMSO-n H2O(n=1,2,3)团簇的拉曼特性,随着水分子的数量增加,体系相互作用能更低,证明了体系更稳定,形成的氢键增多.当水的体积分数达到0.4时,S=O基团的振动发生显著变化,可能发生了相变.这对DMSO/H2O二元混合溶液的内部结构有很大的影响.该研究有助于理解DMSO水溶液中的氢键体系,对于研究溶液中的分子微观结构具有重要意义.
Raman Spectroscopy of DMSO-water Binary Mixed Solutions with Varying Concentrations
In this paper,raman spectral characteristics of dimethyl sulfoxide (DMSO) aqueous solution at different concen-trations were studied. The antisymmetric stretching vibration at 1029 cm-1 is inhibited by the S=O group's apparent new vibration peak at 1017 cm-1 and growing intensity with the increase in water content. Furthermore,the S=O group shows an opposite red shift tendency to the blue shift of the C-S-C group and the CH3 group. Density functional theory was used to calculate quantum chemical characteristics of DMSO-n H2O (n=1,2,3) clusters. The interaction energy of the system decreases significantly as the number of water molecules increases. Since the system is more stable,more hydrogen bonds are produced. The S=O group's vibration considerably changes and a phase transition can happen when the volume fraction of water exceeds 0.4. This significantly affects the internal structure of the binary mixed solution of DMSO and H2O. The understanding of the hydrogen bond system in the DMSO aqueous mixture that this study provides is crucial for our under-standing of the molecular microstructure in solution.
Raman spectroscopyhydrogen bonding,DMSOdensity functional theory
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