Simond Mickaël R, Ballerat-Busserolles Karine, Coxam Jean-Yves, Pádua Agílio A H
Institut de Chimie de Clermont-Ferrand, Université Blaise Pascal Clermont-Ferrand & CNRS , BP 80026, 63171 Aubière, France.
J Chem Theory Comput. 2014 Jun 10;10(6):2471-8. doi: 10.1021/ct5002158. Epub 2014 May 6.
We report a transferable force field to describe the interactions of alkanolamines based on the N-C-C-O backbone with water, derived from a comparison with experimental excess enthalpies. This force field is tested on 2-aminoethan-1-ol (MEA), 2-amino-2-methylpropan-1-ol, 2-aminobutan-1-ol (ABU), and 1-aminopropan-2-ol. These alkanolamines are derivatives of MEA obtained by substitution with methyl and ethyl groups on the carbon atoms of the N-C-C-O backbone. A specific cross interaction site corresponding to the hydrogen bond between the hydroxyl group of the alkanolamine and the oxygen atom of water was introduced in order to reproduce quantitatively experimental excess enthalpies. The transferability of this specific site was assessed by predictions on alkanolamines that were not included in the parametrization data set. New data on enthalpy of mixing for ABU with water are reported, since they were not available in the literature. From the molecular simulations, several microscopic quantities of the alkanolamine-water mixtures were analyzed in order to improve our understanding of these systems. The structure of the solvation shells at varying compositions, statistics of hydrogen bonds, conformations, and energy decompositions served as bases for an interpretation of the molecular reasons underlying the behavior of the excess enthalpy. The prominent result is that water-water interactions play a major role in differentiating alkanolamine-water mixtures, which is a manifestation of the hydrophobic effect. Both the structural and energetic effects observed at the molecular level point to phenomena that have strong composition dependence, in particular, the interplay between the intramolecular hydrogen bond in the alkanolamine and the intermolecular hydrogen bonds with water.
我们报告了一种可转移的力场，用于描述基于N-C-C-O主链的链烷醇胺与水之间的相互作用，该力场源自与实验超额焓的比较。此力场在2-氨基乙醇（MEA）、2-氨基-2-甲基丙醇、2-氨基丁醇（ABU）和1-氨基丙醇-2上进行了测试。这些链烷醇胺是MEA的衍生物，通过在N-C-C-O主链的碳原子上用甲基和乙基取代而获得。为了定量再现实验超额焓，引入了一个与链烷醇胺的羟基和水的氧原子之间的氢键相对应的特定交叉相互作用位点。通过对未包含在参数化数据集中的链烷醇胺进行预测，评估了该特定位点的可转移性。报告了ABU与水混合焓的新数据，因为文献中没有这些数据。通过分子模拟，分析了链烷醇胺-水混合物的几个微观量，以增进我们对这些体系的理解。不同组成下溶剂化壳层的结构、氢键统计、构象和能量分解，为解释超额焓行为背后的分子原因提供了依据。突出的结果是，水-水相互作用在区分链烷醇胺-水混合物中起主要作用，这是疏水效应的一种表现。在分子水平上观察到的结构和能量效应都指向具有强烈组成依赖性的现象，特别是链烷醇胺中的分子内氢键与与水的分子间氢键之间的相互作用。
