The Kinetics and Mechanisms of Main-Group Redox Reactions

本项目为无机、生物无机及有机金属化学专业，主要研究水溶液中主族元素化合物的化学性质。主族元素包括硫、氧、氯、氮和硒，主族化合物的反应涉及各种具有重大经济和社会意义的过程，从普通的氯漂白剂的作用到对环境至关重要的酸雨的形成。该项目的主要重点是氧化和还原主基团化合物，特别是通过自由基中间体。一组反应将使用取代惰性配位化合物作为反应伙伴，这将具有相对可预测的反应机制的优点。Ru（III）配合物对亚硫酸盐的氧化作用将用于估计亚硫酸盐自由基的标准氧化还原电位，并有望证明自由基磺化的新过程。这项研究和相关配合物的研究将用于阐明影响锥体分子中电子转移的因素。Ni（III）配合物氧化NO将被研究，以提供对核隧穿的模糊现象的见解。核隧道效应将在BrCN的球外还原和亚硝酸盐离子和NO氧化的动力学同位素效应的研究中进一步探索。另一类要研究的反应是主基团分子之间的氧化还原反应。双氧/超氧偶联的自交换速率将被直接测量。本课程的其他反应将探讨一个假设，即主基团之间的电子转移速度总是比马库斯理论预测的要快得多。

The focus of this project in the Inorganic, Bioinorganic and Organometallic Chemistry Program is the chemistry of compounds of main-group elements in aqueous solution. Main-group elements include sulfur, oxygen, chlorine, nitrogen and selenium, and the reactions of main-group compounds are involved in a variety of processes of great ecomomic and social importance, ranging from something as mundane as the action of chlorine bleach to the environmentally important formation of acid rain. The primary focus of this project is the oxidation and reduction of main-group compounds, especially through free radical intermediates. One set of reactions will use substitution-inert coordination compounds as the reaction partners, which will have the advantage of relatively predictable reaction mechanisms. Oxidation of sulfite by a Ru(III) complex will be used to estimate the standard redox potential of the sulfite radical, and is expected to demonstrate the novel process of free-radical sulfonation. This and studies with related complexes will be used to elucidate the factors affecting electron transfer at pyramidal molecules. Oxidation of NO by a Ni(III) complex will be studied to provide insight on the obscure phenomenon of nuclear tunneling. Nuclear tunneling will be probed further in studies of the outer-sphere reduction of BrCN and through kinetic isotope effects in the oxidations of nitrite ion and NO. The other class of reactions to be investigated is redox reactions between main-group molecules. The self-exchange rate for the dioxygen/superoxide couple will be measured directly. Other reactions in this class will probe the hypothesis that electron transfer between main-group species invariably proceeds with rates much greater than predicted by Marcus theory.