Predicting hydration Gibbs energies of alkyl-aromatics using molecular simulation: a comparison of current force fields and the development of a new parameter set for accurate solvation data
Predicting hydration Gibbs energies of alkyl-aromatics using molecular simulation: a comparison of current force fields and the development of a new parameter set for accurate solvation data
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DOI：
10.1039/c1cp21245a
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发表时间：
2011-01-01
影响因子：
3.3
通讯作者：
Macedo, Eugenia A.
中科院分区：
文献类型：
--
作者：
Garrido, Nuno M.;Jorge, Miguel;Macedo, Eugenia A.
水化吉布斯自由能是了解恒温恒压下水相体系分子行为的重要物理量。在这项工作中，我们回顾了一些流行的力场，即TrapPE，OPLS-AA和Gromos的性能，在再现实验的吉布斯自由能的几个烷基芳香族化合物的水合苯，单，二，三取代的烷基苯，使用分子模拟技术。在本文的第二部分中，我们报告了一个新的模型，能够提高这样的水化能的预测，从最近的TrapPE-EH力场和原子的部分电荷的密度泛函理论计算的自然布居分析获得的Lennard Jones参数的基础上。我们应用一个比例因子，通过拟合只有两个溶质的实验水合能确定，然后提出了一个简单的规则，以产生不同取代的烷基芳烃原子部分电荷。该规则具有额外的优点，即消除了每个取代的碳原子上固定电荷的不必要假设，并为将电荷分配外推到任何多取代的烷基-芳族分子提供了简单的指导。这里导出的点电荷产生很好的预测实验吉布斯自由能的水化，与小于0.6千焦摩尔（-1）的总体绝对平均偏差。该参数集对其它热力学性质和液体结构信息也有较好的预测效果。
The Gibbs energy of hydration is an important quantity to understand the molecular behavior in aqueous systems at constant temperature and pressure. In this work we review the performance of some popular force fields, namely TraPPE, OPLS-AA and Gromos, in reproducing the experimental Gibbs energies of hydration of several alkyl-aromatic compounds-benzene, mono-, di- and tri-substituted alkylbenzenes-using molecular simulation techniques. In the second part of the paper, we report a new model that is able to improve such hydration energy predictions, based on Lennard Jones parameters from the recent TraPPE-EH force field and atomic partial charges obtained from natural population analysis of density functional theory calculations. We apply a scaling factor determined by fitting the experimental hydration energy of only two solutes, and then present a simple rule to generate atomic partial charges for different substituted alkyl-aromatics. This rule has the added advantages of eliminating the unnecessary assumption of fixed charge on every substituted carbon atom and providing a simple guideline for extrapolating the charge assignment to any multi-substituted alkyl-aromatic molecule. The point charges derived here yield excellent predictions of experimental Gibbs energies of hydration, with an overall absolute average deviation of less than 0.6 kJ mol(-1). This new parameter set can also give good predictive performance for other thermodynamic properties and liquid structural information.