Tailored Force Fields for Modelling Transition-Metal-Mediated Reactions

用于模拟过渡金属介导反应的定制力场

基本信息

批准号：
EP/E00945X/1
负责人：
Robert James Deeth
金额：
$ 26.95万
依托单位：
University of Warwick
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2007
资助国家：
英国
起止时间：
2007 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FE00945X%2F1
关键词：
Tailored Force Fields Modelling Transition

项目摘要

Transition metals play key roles in diverse processes of enormous chemical, industrial and biological significance. The understanding, and hence control, of these processes requires an intimate knowledge of the reaction mechanism - the pathway joining reactants to products. The key feature of this pathway is the species sitting at the mountain pass - the transition state (TS). If you know the structure and energy of the TS, you can predict the outcome of the reaction.However, the TS is a transient, unstable species which is difficult to characterise experimentally. In contrast, the theoretical definition of a TS is straightforward. It is just another point on the potential energy (PE) surface.Unfortunately, whilst the definition may be easy, locating the TS is much trickier but since the TS is so important, theoretical chemists are increasingly devoting themselves to developing new and better ways for finding them.Given that TSs often involve bond making/bond breaking processes, theoretical modelling has usually focussed on fully quantum methods which can treat such processes properly. However, all quantum chemical methods are relatively slow which severly limits the size of molecular system we can study in a reasonable timeframe. The alternative is to use fast classical modelling methods like molecular mechanics providing you can solve the issue that MM is not normally supposed for TS location and, in the context of this proposal, methods specifically targeted at transition-metal-mediated processes. However, the very features that make transition metal (TM) species ideal catalysts, also make them hard to calculate. The current proposal describes an alternative empirical approach: seam searching. The seam describes the intersection of the PE surfaces describing the reactant and product states. The enormous power of the approach is that:1. seam searching is minimisation: all the standard conformational search tools can be employed2. the seam depends only on a reasonable model for the ground states of the reactant and product3. the lowest energy point on the seam is not sensitive to the starting geometry4. the lowest energy point on the seam is a good approximation to the true TSSeam searching thus represents a powerful, general alternative to quantum chemical methods and represents the next leap forward in molecular modelling.

过渡金属在巨大的化学，工业和生物学意义的各种过程中起关键作用。这些过程的理解以及控制需要对反应机制有深入的了解 - 将反应物与产品相连的途径。该途径的关键特征是坐在山口 - 过渡状态（TS）的物种。如果您知道TS的结构和能量，则可以预测反应的结果。但是，TS是一种瞬态的，不稳定的物种，很难在实验上表征。相反，TS的理论定义很简单。这只是势能（PE）表面的另一点。不幸的是，虽然定义很容易，但定位TS非常困难，但是由于TS非常重要，因此理论化学家越来越多地致力于为寻找新的和更好的方式开发新的方法。tss通常涉及键合/键合的过程，通常会努力地进行构建量的方法，而这些方法通常可以构成量的方法，而这些方法通常可以按照量的方式进行量身定制。但是，所有量子化学方法都相对较慢，这严重限制了我们可以在合理的时间范围内研究的分子系统的大小。替代方法是使用快速的经典建模方法，例如分子力学，只要您可以解决MM通常不假定的TS位置，并且在此建议的背景下，专门针对过渡金属介导的过程。但是，使过渡金属（TM）物种理想催化剂的特征也使它们难以计算。当前的建议描述了一种替代的经验方法：接缝搜索。接缝描述了描述反应物和产物态的PE表面的相交。该方法的巨大力量是：1。接缝搜索是最小化：所有标准构象搜索工具都可以使用2。接缝仅取决于反应物和product3的基态的合理模型。接缝上的最低能点对起始几何4不敏感。接缝上的最低能点是与真实TSSEAM搜索的良好近似值，因此代表了量子化学方法的强大，一般的替代方案，代表了分子建模中的下一个飞跃。