Dashnau Jennifer L, Nucci Nathaniel V, Sharp Kim A, Vanderkooi Jane M
Johnson Research Foundation, Department of Biochemistry and Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
J Phys Chem B. 2006 Jul 13;110(27):13670-7. doi: 10.1021/jp0618680.
Molecular dynamics simulations and infrared spectroscopy were used to determine the hydrogen bond patterns of glycerol and its mixtures with water. The ability of glycerol/water mixtures to inhibit ice crystallization is linked to the concentration of glycerol and the hydrogen bonding patterns formed by these solutions. At low glycerol concentrations, sufficient amounts of bulk-like water exist, and at low temperature, these solutions demonstrate crystallization. As the glycerol concentration is increased, the bulk-like water pool is eventually depleted. Water in the first hydration shell becomes concentrated around the polar groups of glycerol, and the alkyl groups of glycerol self-associate. Glycerol-glycerol hydrogen bonds become the dominant interaction in the first hydration shell, and the percolation nature of the water network is disturbed. At glycerol concentrations beyond this point, glycerol/water mixtures remain glassy at low temperatures and the glycerol-water hydrogen bond favors a more linear arrangement. High glycerol concentration mixtures mimic the strong hydrogen bonding pattern seen in ice, yet crystallization does not occur. Hydrogen bond patterns are discussed in terms of hydrogen bond angle distributions and average hydrogen bond number. Shift in infrared frequency of related stretch and bend modes is also reviewed.
利用分子动力学模拟和红外光谱来确定甘油及其与水的混合物的氢键模式。甘油/水混合物抑制冰结晶的能力与甘油浓度以及这些溶液形成的氢键模式有关。在低甘油浓度下，存在足够量的类似本体的水，并且在低温下，这些溶液会发生结晶。随着甘油浓度的增加，类似本体的水池最终会耗尽。第一水合层中的水会在甘油的极性基团周围浓缩，并且甘油的烷基会自缔合。甘油-甘油氢键成为第一水合层中的主要相互作用，并且水网络的渗流性质受到干扰。在超过这一点的甘油浓度下，甘油/水混合物在低温下保持玻璃态，并且甘油-水氢键更倾向于线性排列。高甘油浓度混合物模仿了冰中所见的强氢键模式，但不会发生结晶。从氢键角度分布和平均氢键数方面讨论了氢键模式。还回顾了相关伸缩和弯曲模式的红外频率位移。
