Organometallic Radical Chemistry; Cage Effects and Reactivity in Aqueous Solution

有机金属自由基化学；

• 批准号: 9730436
• 负责人: David Tyler
• 金额: $ 34.1万
• 依托单位: University of Oregon Eugene
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-15 至 2002-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9730436&HistoricalAwards=false
• 关键词: Organometallic; Radical; Chemistry; Cage; Effects

In this project, which is supported by the Inorganic, Bioinorganic, and Organometallic Chemistry Program, Dr. David R. Tyler of the Department of Chemistry, University of Oregon, will continue his studies on organometallic radical reactivity. The first part of the project involves using time-resolved pump/probe spectroscopy and `slow` kinetic methods to measure the cage effect for a series of photochemically and thermally generated organometallic radicals, including substituted cyclopentadienyl compounds of Mo, titanocenes, and cobaloximes. The cage effect refers to the phenomenon that the probability of combination of a radical pair is greater in solution than in the gas phase. Cage effects are necessary to explain kinetic observations and fundamental reaction phenomena for chemical reactivity in solution in all areas of chemistry and biochemistry. Experiments will probe the effect of radical size, shape, and mass on the cage effect. The concepts of `microscopic inertia` and solvent `microviscosity` will be probed as they relate to the cage effect. Radicals with long chains will also be examined as these are directly relevant to polymer and bio-chemistry. The goal of this research is to acquire a predictive understanding of the cage effect. The second part of this project will focus on studies of the reactivity of water soluble organometallic radical species in aqueous solution. Substitution reactions of photochemically and electrochemically generated 17-electron species will be studied, as will oxidatively-induced migratory insertion reactions. The kinetics and activation parameters of these reactions will be determined by infrared spectroscopy and chronocoulometry experiments, with the goal of determining reaction mechanisms. Electron-transfer-chain reactions catalyzed by organometallic radicals will also be studied with an emphasis on determining the differences in radical reactivity between aqueous and nonaqueous solutions. Several new water soluble phosphine ligands will also be synthesized and tested in biphasic hydroformylation and hydrogenation catalysis experiments using Rh complexes. This project will provide useful and fundamentally important information on the nature of reactions in solution that involve radicals, reactive chemical compounds with an odd number of electrons. Radical reactions are ubiquitous in chemistry and biochemistry and include polymerization reactions (plastics and fibers) and life sustaining enzyme reactions. Results of the work with water soluble organometallic catalysts will be fundamental and practical. Most chemicals produced in industry involve catalysis and many processes use volatile and toxic organic solvents. There are compelling environmental reasons to develop catalysts that can use water as a solvent.

在这个项目中，这是由无机，生物无机， 有机金属化学项目，大卫·R博士。司法部的泰勒 化学，俄勒冈州大学，将继续他的研究 有机金属自由基反应性。 项目的第一部分 涉及使用时间分辨泵浦/探测光谱和“慢”动力学 方法来测量笼效应的一系列光化学和 热生成的有机金属基团，包括取代的 钼、二茂钛和钴肟的化合物。 笼子 效应是指一种组合的概率 自由基对在溶液中比在气相中更大。 笼效应 是解释动力学观测和基本反应所必需的 在所有化学领域中溶液中的化学反应现象 和生物化学。 实验将探索原子团大小的影响， 形状和质量对笼子效应的影响 微观的概念 惯性“和溶剂”微粘度“将被探测，因为它们与 笼子效应。 具有长链的自由基也将被检查为 这些与聚合物和生物化学直接相关。 的目标 这项研究是为了获得一个预测性的了解笼 效果 本项目的第二部分将侧重于研究 水溶性有机金属自由基物种在水中的反应性 溶液 光化学取代反应和 电化学产生的17电子物种将被研究，因为将 氧化诱导的迁移插入反应。 的动力学和 这些反应的活化参数将通过红外光谱测定。 光谱学和计时库仑实验，目标是 确定反应机制。 电子转移链反应 催化的有机金属自由基也将研究与 重点是确定自由基反应性的差异， 水溶液和非水溶液。 几种新的水溶性膦 还将合成配体，并在两相水溶液中进行测试。 和使用Rh络合物的氢化催化实验。 这个项目将提供有用的和根本重要的信息 关于溶液中涉及自由基的反应的性质， 具有奇数个电子的化合物。 基反应 在化学和生物化学中普遍存在， 反应（塑料和纤维）和维持生命的酶反应。 水溶性有机金属催化剂的工作结果将是 基础性和实用性。 工业生产的大多数化学品都涉及 催化和许多方法使用挥发性和有毒的有机溶剂。 有令人信服的环境原因来开发催化剂， 使用水作为溶剂。