Rational Reaction Promoter and Ligand Design in Synthesis

非技术性：在这个由化学系化学催化项目资助的项目中，Gerald B教授。路易斯维尔大学的哈蒙德正在提高化学合成中离子反应的效率。 离子反应，根据定义涉及带电物质，是化学合成中最常见的反应。这种合成在药物、材料、农用化学品和许多其他相关领域中起着至关重要的作用。该项目的更广泛的影响包括培训博士后研究员和研究生和本科生，并通过专题讨论会提高拉美裔美国学生的招聘机会，其中包括知名的拉美裔美国化学家，以及与拉丁美洲教师的科学合作。这项工作对制造业产生了广泛的影响，因为它提供了能够简化化学合成的催化剂和促进剂。技术：离子是分离还是相互结合取决于溶剂的极性。 在低介电常数溶剂中，离子通常以离子对形式存在。成对工作离子的反应性被认为低于相应的“自由”离子，尽管还没有系统的方法来定量或数学地理解离子反应中离子配对的影响。在大多数离子反应的理论和实验研究中，反离子被简单地忽略了。该项目所支持的假设是，离子反应中的过渡态结构在尺寸上大于起始离子对，并且被反离子扭曲。要进行的工作应导致反应促进剂和配体的设计，这将减少离子配对的阻碍效应，这反过来可能导致离子反应中更高的反应性。该研究为制备具有广泛应用前景的反应促进剂、聚合物键合型反应促进剂、手性反应促进剂以及手性超强布朗斯台德酸提供了新的途径。此外，大体积配体将用于阳离子金催化和其它阳离子金属催化--有或没有反应促进剂--最终目标是引入新一代阳离子金属催化剂，其在温和的反应条件下在ppm水平负载下具有前所未有的反应性。在典型的反应系统中的离子配对的实验研究，并开发计算方法来测量离子对中的离子之间的距离，以及离子的大小，使用计算化学技术由合作者，英国牛津大学的Robert Paton教授进行。

Nontechnical: In this project, funded by the Chemical Catalysis program of the Chemistry Division, Professor Gerald B. Hammond, of the University of Louisville, is improving the efficiency of ionic reactions in chemical synthesis. Ionic reactions, involving by definition charged species, are the most common reactions used in chemical synthesis. Such synthesis plays a vital role in pharmaceuticals, materials, agrochemicals and many other related fields. The broader impacts of this project involve training postdoctoral fellows and graduate and undergraduate students, and enhancing the recruitment opportunities of Hispanic American students through symposia featuring high-profile Hispanic-American chemists, and scientific collaborations with Latin American faculty. The proposed work impacts the manufacturing industry broadly defined because it gives ready access to catalysts and promoters capable of streamlining chemical syntheses.Technical: Whether ions are separated or associated with each other depends on the polarity of the solvent. In low dielectric constant solvents, ions usually exist as ion pairs. The reactivity of a paired working ion is considered lower than the corresponding 'free' ion although there has been no systematic approach to understand, in quantitative or mathematical terms, the effect of ion pairing in ionic reactions. In most theoretical and experimental studies of ionic reactions, counterions are simply ignored. The hypothesis espoused in this project is that the transition state structure in an ionic reaction is bigger in size than the starting ion pair and is distorted by the counterion. The work to be carried out should lead to the design of reaction promoters and ligands that will reduce the hindrance effect of ion pairing, which, in turn, may lead to higher reactivity in ionic reactions. This research makes available broadly applicable reaction promoters, polymer-bound reaction promoters, and chiral reaction promoters, as well as chiral super strong Bronsted acids. In addition, bulky ligands are to be utilized in cationic gold catalysis and other cationic metal catalysis--with or without a reaction promoter--with the ultimate goal of ushering in a new generation of cationic metal catalyst with unprecedented reactivity at ppm level loadings under mild reaction conditions. Experimental investigations of ion pairing in typical reaction systems, and developing calculation methods to measure the distance between ions in an ion pair, as well as the size of ions, are performed using computational chemistry techniques by a collaborator, Professor Robert Paton, from Oxford University, England.