Novel Probes of Photochemical Mechanisms

本项目将研究其结构、化学性质、光反应性以及阴离子、稳定自由基和自由基生成的新途径。这些中间体的结构将通过固相和固相核磁共振波谱的比较、电化学技术以及采用瞬态和稳态照明作为激发态反应性的探针来确定。特别感兴趣的将是确定结构如何影响若干家族的阴离子、自由基离子和稳定自由基的酸度和氧化电位。基本的热化学信息将通过将光化学和热电子传递速率与由高速循环伏安法或光电调制伏安法得出的氧化还原电位相关联来获得。在超临界流体中探索光化学的新方向将寻求在严格控制的条件下探测溶剂化效应。在这些研究中，将探讨聚集、环境和溶剂化如何影响化学反应性的科学重要问题，特别是电子转移反应。这项来自有机动力学项目的拨款支持了德克萨斯大学奥斯汀校区Marye Anne Fox教授的持续工作。这项研究将产生关于化学反应中活性中间体的基本性质的结果。有机化学的机理基础是建立在对反应性中间体的性质及其在化学转化中的作用的理解之上的。对这些中间体的了解将使化学家能够更好地预测化学反应的过程。

The structure, chemical properties, photoreactivity, and new routes for the generation of anions, stable radicals, and radical ions will be investigated in this project. Structure will be determined for these intermediates by a comparison of solution phase and solid state nmr spectroscopy, by electrochemical techniques, and by employing transient and steady state illumination as probes for excited state reactivity. Of particular interest will be the determination of how structure influences the acidities and oxidation potentials of several families of dianions, radical ions, and stable radicals. Fundamental thermochemical information will be attained by correlating rates of photochemical and thermal electron transfer with redox potentials derived by high speed cyclic voltammetry or photomodulation voltammetry. A new thrust exploring photochemistry in supercritical fluids will seek to probe solvation effects under carefully controlled conditions. In these studies, scientifically important questions will be probed of how aggregation, environment, and solvation affect chemical reactivity, particularly electron transfer reactions. This grant from the Organic Dynamics Program supports the continuing work of Professor Marye Anne Fox at the University of Texas, Austin Campus. This research will generate results of a fundamental nature about reactive intermediates in chemical reactions. The mechanistic basis of organic chemistry rests on an understanding of the properties of reactive intermediates and their involvement in chemical transformations. Knowledge of these intermediates will provide chemists with a better ability to predict the course of chemical reactions.