Solvent Size vs Cohesive Energy as the Origin of Hydrophobicity
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- 作者：Themis Lazaridis
- 刊名：Accounts of Chemical Research
- 出版年：2001
- 出版时间：December 2001
- 年：2001
- 卷：34
- 期：12
- 页码：931 - 937
- 全文大小：87K
- 年卷期：v.34,no.12(December 2001)
- ISSN：1520-4898
文摘
Two main physical explanations of hydrophobicity seem to becurrently competing. The classical, intuitive view attributes it tothe fact that interactions between water molecules are muchstronger than those between water and nonpolar groups. Thesecond, "heretic" view attributes it to the small size of the watermolecule which increases the entropic cost of opening up a cavityto accommodate the solute. Here we examine the solvation ofmethane in water and in model liquids that lack one or more ofwater's properties and report a detailed decomposition of thesolvation free energy, enthalpy, entropy, and heat capacity in thesesolvents. The results fully support the classical view. It is foundthat fluids with strong intermolecular interactions favor expulsionof methane to its pure phase or to CCl4, whereas fluids with weakintermolecular interactions do not. However, the specific thermodynamic signature of the hydrophobic effect (entropy driven atroom temperature with a large heat capacity change) is a result ofthe hydrogen-bonding structure of water.