Interfaces and chirality: Molecular dynamics simulations of enantioseparations

一个“手性”分子有一个孪生体，这个孪生体是一个镜像——就像右手的反射是左手一样。分子双胞胎被称为对映体，在化学合成中，它们通常是一起产生的。许多药物都有镜像，但像立普妥和普拉维这样的药物是以单对映体的形式出售的（只有双胞胎中的一个）。为什么?对许多药物来说，活性存在于一种对映体中，而另一种对映体可能具有完全不同的效果。这种差异就是为什么分离对映体在药物开发、农业化学品、食品添加剂、香水和其他产品的生产中很重要的原因。分离对映体的实验技术已经发展起来，这些方法使用第三种手性分子——选择器——与每个对映体配对。这对是不同的，理想情况下，差异足够大，可以实现分离。

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.