Interfaces and chirality: Molecular dynamics simulations of enantioseparations

“手性”分子有一对双胞胎，双胞胎是镜像--就像右手的反射是左手一样。双胞胎分子被称为对映体，在化学合成中，他们通常是一起产生的。许多药物都有镜像，但立普妥和Plavix等药物是作为单一对映体出售的(双胞胎中只有一种)。为什么？对于许多药物来说，活性取决于一种对映体，而另一种可能具有完全不同的效果。这就是为什么分离对映体在药物开发以及农用化学品、食品添加剂、香水和其他产品的生产中非常重要的原因。已经开发了分离对映体的实验技术，这些方法使用第三个手性分子-选择器-与每个对映体配对。这些对是不同的，理想情况下，差异足够大，可以实现分离。拟议的工作应用分子动力学模拟来解决与拆分对映体相关的问题。在接下来的五年里，我们将：1)设计和测试新的表面结合手性选择剂，目标是识别那些可预测地随着溶剂的变化而改变其性质的手性选择剂。这些选择剂将提供一种控制和改进手性分离的简单方法。2)研究外加电场时手性选择器的有效性，以深入了解实验情况。3)在拆分对映体的实验中，通常存在无定形二氧化硅表面，我们将密切关注这些表面。4)手性分子对环境的影响，我们将研究手性在有序流体中的传递。在拟议的研究计划过程中，五名博士生、一名博士后研究员和几名本科生将接受手性系统分子动力学模拟的专门培训。高性能计算在经济、医学、科学等领域日益重要。所有学员将熟悉高性能计算和最先进的并行编程。

A "chiral" molecule has a twin, and the twin is a mirror image - just like the reflection of a right hand is a left hand. Molecular twins are called enantiomers and in a chemical synthesis, they are often produced together. Many pharmaceuticals have mirror images but drugs such as Lipitor and Plavix are sold as single enantiomers (only one of the twins). Why? For many drugs, activity resides with one enantiomer and the other may have an entirely different effect. This difference is the reason why separating enantiomers is important in drug development, and for the production of agrichemicals, food additives, perfumes, and other products. Experimental techniques have been developed to separate enantiomers and these methods use of a third chiral molecule - a selector - that pairs up with each of the enantiomers. The pairs are different and, ideally, the difference is big enough that a separation can be achieved. The proposed work applies molecular dynamics simulations to address questions relevant to the separation of enantiomers. In the next five years, we will: 1) design and test new surface-bound chiral selectors with the goal of identifying ones that predictably alter their properties with changes in solvent. These selectors will provide a simple means to control and improve a chiral separation. 2) The effectiveness of a chiral selector when a field is applied will be studied to gain insight into experiments. 3) Amorphous silica surfaces are often present in experiments that separate enantiomers and we will look closely at these surfaces. 4) Chiral molecules impact their environment and we will study the transfer of chirality in ordered fluids. Five doctoral students, one postdoctoral researcher, and several undergraduate students will receive specialized training in molecular dynamics simulations of chiral systems during the course of the proposed research program. High performance computing is increasingly important in economics, medicine, science, and other areas. All trainees will become familiar with high performance computing and state-of-the-art parallel programming.