Structural thermodynamics of hydration
Structural thermodynamics of hydration
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DOI：
10.1021/jp0115244
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发表时间：
2001-12-20
影响因子：
3.3
通讯作者：
Chalikian, TV
中科院分区：
文献类型：
--
作者：
Chalikian, TV
本文提出了一个简单的溶质水化双态结构模型。在该模型中，假设本体中的水、状态和溶质水合的水由两种结构物种组成：高密度/高焓物种，结构上类似于冰III，和低密度/低焓物种，结构上类似于冰I。假设本体水和水合水之间的结构和热力学区别仅源自微分分数组成，而与每种物质相关的两种结构物质和热力学参数对于本体水和水合水是相同的。和非极性基团。带电和极性基团的水化的两种结构物种之间的平衡向高密度/高焓物种移动。相比之下，两种水溶剂化非极性基团之间的平衡向低密度/低焓物质移动。溶剂重组被发现是有害的任何原子团独立于其化学性质。然而，溶剂重组的焓、熵和热容强烈地依赖于溶剂暴露基团的化学性质。总的来说，我们的研究结果提供了更可靠的解释的热力学数据在水化方面的基础。此外，这些结果强调的重要性和潜在的有用性相结合的体积和量热数据的微观事件，特别是溶质水化的一个更完整的热力学描述。
A simple two-state structural model Of Solute hydration has been developed. In this model, both water in the bulk, state and water of solute hydration are assumed to consist of two structural specie,s: a high density/high enthalpy species, structurally similar to ice III, and a low density/low enthalpy species, structurally similar to ice I. It is assumed that structural and thermodynamic distinctions between bulk and hydration water originate solely from the differential fractional composition, whereas the two structural species and thermodynamic parameters associated with each species are identical for bulk and hydration water, This model has been used in conjunction with volumetric data reported in the literature to analyze the hydration properties of charged, polar, and nonpolar groups at 25 degreesC. The equilibrium between the two structural species of water of hydration of charged and polar groups is shifted toward the high density/high enthalpy species. In contrast, the equilibrium between the two species of water solvating nonpolar groups is shifted toward the low density/low, enthalpy species. Solvent reorganization was found to be thermodynamically unfavorable for any atomic group independent of its chemical nature. However, the enthalpy, entropy, and heat capacity of solvent reorganization are strongly dependent on the chemical nature of solvent exposed group. In the aggregate, Our results provide foundation for more reliable interpretations of thermodynamic data in terms of hydration. In addition, these results underscore the importance and potential usefulness OF combining volumetric and calorimetric data for a more complete thermodynamic description of microscopic events, in particular, solute hydration.