Investigations of the Cage Effect and Aqueous Organometallic Radical Chemistry

美国俄勒冈大学化学系David R.Tyler博士由化学部无机化学、生物无机化学和金属有机化学项目资助，致力于研究金属有机自由基的反应性。作为研究的一部分，将探讨笼子效应，即导致自由基对在溶液中的反应性比在气相中更大的效应。对于各种质量、大小和形状不同的自由基对，将积累各种“笼子效率因子”，即表示自由基笼子对组合效率的数字。这些数据将提供对笼子效应的预测性理解。该项目的第二部分涉及17电子和19电子有机金属物种在水溶液中的反应性研究。将开发产生水溶性有机金属自由基的新方法，并将对这些自由基的基本反应性和催化性能进行系统化。化合物中的每个电子通常与另一个电子配对。然而，有些化合物含有不成对的电子。这些被称为自由基，它们通常具有相当的化学反应活性，人们越来越意识到它们参与了许多化学过程。该项目的目的是揭示控制含有金属的自由基的化学行为的原理，并开发可溶于水的自由基。由于水是一种环境友好的溶剂，在水溶液中产生自由基的能力将使通常必须在有机溶剂中进行的反应能够在污染较少的介质中进行。

Dr. David R. Tyler, Chemistry Department, University of Oregon, is supported by the Inorganic, Bioinorganic, and Organometallic Chemistry Program of the Chemistry Division for studies on the reactivity of organometallic free radicals. As one portion of the investigation the cage effect, i.e. the effect responsible for the greater reactivity of a radical pair in solution than in the gas phase, will be probed. A variety of `cage efficiency factors`, a number that expresses the efficiency of radical cage pair combinations, will be accumulated for a variety of radical pairs which differ in mass, size, and shape. These data will provide predictive understanding of the cage effect. The second part of the project involves an investigation of the reactivity of 17- and 19-electron organometallic species in aqueous solution. New methods for generating water soluble organometallic radicals will be developed and the fundamental reactivity and catalytic properties of the radicals will be systematized. Each electron in a chemical compounds is usually paired with another. However, there are some compounds which contain an unpaired electron. These are called radicals, they often are quite chemically reactive, and there is a growing realization that they are involved in many chemical processes. The object of this project is to uncover the principles which control the chemical behavior of metal containing radicals and to develop radicals which can dissolve in water. Since water is an environmentally friendly solvent, the ability to generate radicals in aqueous solutions will permit reactions which normally must be carried out in organic solvents to be performed in a less polluting medium.