Radical Cage Effects in Organometallic Chemistry

有机金属化学中的自由基笼效应

• 批准号: 0452004
• 负责人: David Tyler
• 金额: --
• 依托单位: University of Oregon Eugene
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-15 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0452004&HistoricalAwards=false
• 关键词: Radical; Cage; Effects; Organometallic; Chemistry

This award in the Inorganic, Bioinorganic and Organometallic Chemistry program supports Professor David Tyler at the University of Oregon to investigate the fundamental, underlying principles of the cage effect in radical reaction chemistry. The still-confusing role of the solvent will be explored using a new model based on the "microviscosity" of the solvent. Another part of the research will focus on what effect the wavelength of light has on the cage effect in photogenerated radical cage pairs. Preliminary results show a trend opposite to that predicted by theory. Other experiments will probe spin effects on the recombination of two metal radicals, which has not been systematically addressed until now. Another set of experiments will examine the effects of radical mass, size, and shape on the cage effect. In particular, it is proposed that the ratio of the rate constants for cage escape to cage recombination is proportional to the square root of the mass divided by the surface area of the radical. This hypothesis will be tested with radicals of various masses and sizes. If this relationship is general, it will give researchers a powerful tool for predicting cage recombination efficiencies. Femtosecond timescale laser pump-probe experiments will be used to directly observe the shortlived radical cage pair. In these experiments, the cage effect for two randomly colliding radicals will be studied relative to the cage effect for a radical cage pair formed by bond homolysis. As former radicals initially have a random orientation when they meet in a cage, whereas the latter radicals are initially aligned, this difference may show up as a difference in the cage effect and in the reactivity of the cage pair. Graduate students will participate in successful internship programs, which prepare Ph.D. students for successful careers in industry or teaching by placing them in regional companies or in colleges for a one-term internship experience. The research described herein has also fostered closer ties to regional companies and colleges in the form of collaborative research projects. This has led to professors at regional colleges taking sabbatical leaves in the Professor Tyler's laboratory and to students at such colleges and companies using the instrumentation in the University of Oregon Department of Chemistry.

该奖项在无机，生物有机和有机金属化学计划中支持俄勒冈大学的戴维·泰勒教授，以研究笼子效应的基本基本原理在根本性反应化学中。 溶剂的仍然存在的作用将使用基于溶剂的“微粘度”的新模型来探索。 研究的另一部分将重点介绍光波长对光生自由基笼子对的笼子效应的影响。初步结果显示出与理论预测的趋势相反。 其他实验将探测两种金属自由基重组的自旋影响，直到现在尚未系统地解决。 另一组实验将检查根部质量，大小和形状对笼子效应的影响。 特别是，有人提出，笼子逃逸与笼子重组的速率常数与质量的平方根成正比，该平方根除以自由基的表面积。 该假设将通过各种质量和大小的自由基进行检验。如果这种关系是一般的，它将为研究人员提供一个预测笼子重组效率的强大工具。飞秒时间尺度激光泵探针实验将用于直接观察短的自由基笼子对。 在这些实验中，将研究两个随机碰撞的自由基的笼子效应相对于由键同型形成的自由基笼对的笼子效应。 由于以前的自由基在笼子中相遇时最初具有随机取向，而后一种自由基最初是对齐的，因此这种差异可能显示为笼子效应和笼子对的反应性的差异。 研究生将参加成功的实习计划，该计划准备博士学位。通过将他们置于区域公司或大学中的一项实习经验，从事行业或教学成功职业的学生。 本文所述的研究还以协作研究项目的形式与区域公司和学院建立了更紧密的联系。 这导致了区域学院的教授在泰勒教授的实验室里放假叶，并使用俄勒冈大学化学系的仪器的该学院和公司的学生。