Interfacial Behavior of Ionophoric Systems: Molecular Dynamics Studies on 18-Crown-6 and Its Complexes at the Water-Chloroform Interface
Interfacial Behavior of Ionophoric Systems: Molecular Dynamics Studies on 18-Crown-6 and Its Complexes at the Water-Chloroform Interface
复制标题
离子传递体系的界面行为：18-Crown-6及其配合物在水-氯仿界面的分子动力学研究
DOI：
--
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
G. Wipff
中科院分区：
文献类型：
--
作者：
L. Troxler;G. Wipff
我们使用溶剂的显式表示，报告了在水-氯仿界面处对 18-crown-6 (18C6) 未络合及其 K^+Pic^- 络合物进行的一系列分子动力学模拟。 (18C6)_10 聚集体最初位于界面，1 ns 后在界面吸附的分子与扩散到有机相的其他分子之间显示出复杂的平衡。 (18C6·K^+Pic^-)_6 包含络合物最初位于界面，1 ns 后也显示出 18C6 分子、18C6·K^+ 络合物和吸附在界面上的 Pic^- 抗衡离子之间的平衡，而一些解络的 K^+ 阳离子被水捕获。还观察到 18C6·K^+ 配合物在特定水分子和 Pic^- 抗衡离子的促进下自发迁移到有机相。与 (18C6·K^+Pic^-)_1 和 (18C6·Sr^2+_2Pic^-)_1 配合物的模拟比较突出了浓度和阳离子电荷对界面行为的影响。我们最后描述了一个“计算机萃取实验”，该实验从有机相中的 18C6 分子和水中的 K^+Pic^- 离子对开始。结合实验数据讨论结果。我们强调游离和络合萃取剂分子的类表面活性剂行为、界面诱导的离子载体的预组织以及抗衡离子的作用。表面活性阴离子吸引界面处的阳离子并促进它们被吸附的离子载体捕获。协同效应应由共萃取剂分子或/和反离子在界面处的吸附产生。
We report a series of molecular dynamics simulations on 18-crown-6 (18C6) uncomplexed, and on its K^+Pic^- complexes, at the water-chloroform interface, using an explicit representation of the solvents. The (18C6)_10 aggregate, initially at the interface, displays after 1 ns a complex equilibrium between molecules adsorbed at the interface, and others which have diffused to the organic phase. The (18C6·K^+Pic^-)_6 inclusive complexes, initially at the interface, also display after 1 ns, an equilibrium between 18C6 molecules, 18C6·K^+ complexes and the Pic^- counterions adsorbed at the interface, while some decomplexed K^+ cations are captured by water. The spontaneous migration of a 18C6·K^+ complex to the organic phase is also observed, facilitated by specific water molecules and the Pic^- counterions. Comparison with simulations on the (18C6·K^+Pic^-)_1 and (18C6·Sr^2+_2Pic^-)_1 complexes highlights the effect of concentration and of the cationic charge on the interfacial behavior. We finally describe a “computer extraction experiment”, which starts with 18C6 molecules in the organic phase and K^+Pic^- ion pairs in water. The results are discussed in relation with experimental data. We emphasize the surfactant-like behavior of free and complexed extractant molecules, the preorganization of ionophores induced by the interface, and the role of counterions. Surface active anions attract the cations at the interface and facilitate their capture by the adsorbed ionophores. Synergistic effects should result from the adsorption of co-extractant molecules or/and of counterions at the interface.
DOI：
10.1063/1.471030
发表时间：
1996-03
期刊：
The Journal of chemical physics
影响因子：
--
作者：
A. Pohorille;M. Wilson
通讯作者：
A. Pohorille;M. Wilson
麻醉剂与膜-水界面的相互作用。
影响因子：
2.3
作者：
Pohorille,A;Cieplak,P;Wilson,MA
通讯作者：
Wilson,MA