Quantifying Hydrogen-Bond Populations in Dimethyl Sulfoxide/Water Mixtures
Quantifying Hydrogen-Bond Populations in Dimethyl Sulfoxide/Water Mixtures
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DOI：
10.1002/anie.201704162
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发表时间：
2017-09-11
影响因子：
16.6
通讯作者：
Baiz, Carlos R.
中科院分区：
文献类型：
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作者：
Oh, Kwang-Im;Rajesh, Kavya;Baiz, Carlos R.
二甲亚砜 (DMSO) 会破坏水中的氢键网络。 DMSO 作为助溶剂的广泛使用及其不寻常的属性激发了许多研究。在此，S=O伸缩模式的红外吸收光谱结合分子动力学和量子化学模型被用来直接量化二元混合物中的DMSO/水氢键群体。由于 DMSO-水的强烈相互作用，单氢键物质占主导地位，占 10 mol%。我们发现非氢键 DMSO 在共晶点附近意外增加（约 35 mol%），这也与本体溶液性质的一些异常相关。我们发现了三种不同状态的证据：1) 强 DMSO-水相互作用 (< 30 mol%)，2) 理想溶液状 (30-90 mol%)，3) 自相互作用或聚集状态 (> 90 mol%)。我们提出了一种“介入”机制，其中涉及水和 DMSO 聚集体物质之间的氢键。
Dimethyl sulfoxide (DMSO) disrupts the hydrogen-bond networks in water. The widespread use of DMSO as a cosolvent, along with its unusual attributes, have inspired numerous studies. Herein, infrared absorption spectroscopy of the S=O stretching mode combined with molecular dynamics and quantum chemistry models were used to directly quantify DMSO/water hydrogen-bond populations in binary mixtures. Singly H-bonded species are dominant at 10 mol%, due to strong DMSO-water interactions. We found an unexpected increase in non-hydrogen-bonded DMSO near the eutectic point (ca. 35 mol%) which also correlates with several abnormalities in the bulk solution properties. We find evidence for three distinct regimes: 1) strong DMSO-water interactions (< 30 mol%), 2) ideal-solution-like (30-90 mol%), and 3) self-interaction, or aggregation, regime (> 90 mol%). We propose a "step in" mechanism, which involves hydrogen bonding between water and the DMSO aggregate species.