Lehrstuhl für Technische Thermodynamik (LTT) and Erlangen Graduate School in Advanced Optical Technologies (SAOT), Universität Erlangen-Nürnberg, Am Weichselgarten 8, 91058 Erlangen, Germany.
Chemphyschem. 2010 Feb 22;11(3):630-7. doi: 10.1002/cphc.200900691.
The effects of hydrogen bonding between dimethyl sulfoxide (DMSO) and the co-solvents water, methanol, and ethanol on the symmetric and antisymmetric CSC stretching vibrations of DMSO are investigated by means of Raman spectroscopy. The Raman spectra are recorded as a function of co-solvent concentration and reflect changes in structure and polarizability as well as hydrogen-bond donor and acceptor ability. In all cases studied a nonideal mixing behavior is observed. The spectra of the DMSO/water system show blue-shifted CSC stretching modes. The antisymmetric frequencies are always further blue-shifted than the symmetric stretching ones. The DMSO/methanol system also features blue-shifted CSC stretching frequencies but at high mole fractions a pronounced red shifting is observed. In the binary DMSO/ethanol system, the co-solvent also gives rise to blue shifts of the CSC stretching frequencies but restricted to mole fractions between x=0.38 and 0.45. The different magnitudes and occurrences of both blue- and red-shifted spectral lines are comprehensively and critically discussed with respect to the existing literature concerning wavenumbers and Raman intensities in both absolute and normalized values. In particular, the normalized Raman intensities show a higher sensitivity for the nonideal mixing behavior because they are independent of the mole fraction.
通过拉曼光谱研究了二甲基亚砜（DMSO）与水、甲醇和乙醇共溶剂之间氢键对 DMSO 对称和反对称 CSC 伸缩振动的影响。拉曼光谱作为共溶剂浓度的函数进行记录，反映了结构和极化率以及氢键供体和受体能力的变化。在所研究的所有情况下，均观察到非理想混合行为。DMSO/水体系的光谱显示 CSC 伸缩模式蓝移。反对称频率总是比对称伸缩频率进一步蓝移。DMSO/甲醇体系也具有 CSC 伸缩频率的蓝移，但在高摩尔分数下观察到明显的红移。在二元 DMSO/乙醇体系中，共溶剂也会导致 CSC 伸缩频率的蓝移，但仅限于 x=0.38 和 0.45 之间的摩尔分数。综合和批判性地讨论了不同幅度和出现的蓝移和红移谱线，参考了关于绝对和归一化值中波数和拉曼强度的现有文献。特别是，归一化拉曼强度对非理想混合行为具有更高的灵敏度，因为它们独立于摩尔分数。
