Molecular model of hydrophobic solvation

被引:108
作者
Silverstein, KAT
Haymet, ADJ
Dill, KA
机构
[1] Univ Houston, Dept Chem, Houston, TX 77204 USA
[2] Univ Calif San Francisco, Grad Grp Biophys, San Francisco, CA 94143 USA
[3] Univ Calif San Francisco, Dept Pharmaceut Chem, San Francisco, CA 94143 USA
关键词
D O I
10.1063/1.480133
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The physical basis for the "hydrophobic effect" is studied using a simple statistical mechanical model of water, the "MB" model, in which water molecules are represented as Lennard-Jones disks with hydrogen bonding arms. Using a four-state framework developed by Muller [Acc. Chem. Res. 23, 23 (1990)], and extended by Lee and Graziano [J. Am. Chem. Soc. 118, 5163 (1996)], we find the model reproduces the fingerprints of hydrophobicity, namely, the large positive heat capacity, and temperatures T-H and T-S at which the enthalpy and entropy of transfer, respectively, are zero. Further, the behavior can be interpreted readily in terms of hydrogen bonds that are either made or broken in the bulk or in the first solvation shell around a nonpolar solute. We find that inserting a nonpolar solute into cold water causes ordering and strengthening of the H bonds in the first shell, but that the reverse applies in hot water. This provides a physical interpretation for the crossover temperatures T-H and T-S. (C) 1999 American Institute of Physics. [S0021-9606(99)51141-0].
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页码:8000 / 8009
页数:10
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