Hydride Transfer and Rates of Transport Across Synthetic Membranes

这个项目由Maurice Kreevoy博士在有机动力学项目中进行，旨在更好地理解一个重要的有机反应，即氢化物转移。这个问题将在理论上通过计算详细的反应途径来解决，在实验上通过测量反应速率来解决。这项工作具有重要意义，因为所研究的反应是酶催化氧化还原反应的原型。借助Truhlar POLYRATE程序，可以生成氢化物转移反应的多维势面。利用最小作用隧穿的变分跃态理论，模拟实验观察到的速率与平衡常数之间的关系、初级和次级氢同位素效应的大小以及初级同位素效应与平衡常数之间的关系。本课题第二部分将研究1-苄基-3-氰基-喹啉离子与10-甲基-9,10-二氢吖啶模型氢化物转移反应的速率常数、一次动力学同位素效应和平衡常数对溶剂的依赖关系。本研究的目的是：建立和测试一个反应模型，以便于确定溶剂对反应活性的动态影响；确定与这种效果成比例的参数；并将其与现有理论及其它溶剂效应的实验方法进行了比较。动态溶剂效应是那些在传统的准平衡过渡态理论中没有考虑到的效应。

This project by Dr. Maurice Kreevoy within the Organic Dynamics Program is aimed at a better understanding of an important organic reaction known as hydride transfer. The problem will be approached theoretically by calculation of the detailed reaction pathway, and also experimentally by the measurement of reaction rates. This work is quite significant in that the reaction to be studied is a prototype for enzyme catalyzed oxidation-reduction reactions. With the aid of the Truhlar POLYRATE program, a multi-dimensional potential surface will be generated for the hydride transfer reaction. Using variational transition state theory with least-action tunneling, it will be used to mimic the experimentally observed relationship between rate and equilibrium constants, the magnitude of primary and secondary hydrogen isotope effects, and the relation between primary isotope effects and equilibrium constants. In the second part of this project, the solvent dependence of the rate constant, primary kinetic isotope effect, and equilibrium constant of the model hydride transfer reaction between 1-benzyl-3-cyano- quinolinium ion and 10-methyl-9,10-dihydroacridine will be studied. The object of this investigation is as follows: to establish and test a model for the reaction that will facilitate the identification of dynamic solvent effects on reactivity; to determine a parameter proportional to such effects; and to compare it with current theory and other experimental measures of dynamic solvent effects. Dynamic solvent effects are those that are not accounted for in conventional, quasi-equilibrium, transition state theory.