Reactions in Organized and Constricted Systems

有组织和受限系统中的反应

• 批准号: 9204420
• 负责人: J. Kerry Thomas
• 金额: $ 39.45万
• 依托单位: University of Notre Dame
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-06-15 至 1996-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9204420&HistoricalAwards=false
• 关键词: Reactions; Organized; Constricted; Systems

The ability of molecular cations to migrate and undergo chemical reactions will be determined in a variety of different environments including low viscosity liquids at room temperature, glasses at 77 K, and highly viscous oligomers and polymers. Polymers to be investigated range from chloropolymers such as polyvinylchloride to polystyrene and polyethylene. The cationic species will be generated by exposure of polycyclic hydrocarbons such as anthracene, naphthalene, and pyrene to high-energy radiation produced from a Fabretron. The resulting cationic species will be detected by transient spectroscopy on a picosecond time scale. In addition to the kinetic analysis of the cation migration rate, an investigation of the rate of fluorescence quenching of both absorbed and surface bound pyrene at solid-air and solid-liquid interfaces of silicon oxide will be conducted. The effect of the surface on the generation of charged species from exciplexes will also be determined by diffuse reflectance transient absorption spectroscopy. The results of these investigations will lead to a better understanding of the reactions of cationic species at surfaces and the factors governing efficient quenching processes. %%% This grant from the Organic Dynamics Program supports the continuing work of Professor J. Kerry Thomas at the University of Notre Dame. The studies will be directed toward understanding the effect of surfaces on the reactivity of chemical substances and will provide critical data which will allow the development of more efficient chemical systems. The investigation will utilize equipment capable of detecting events on the order of less than a billionth of a second. Thus it will be possible to measure the rapid hopping of charged species in a variety of media. The use of target molecules which undergo rapid fluorescence decay processes provides a means of monitoring chemical processes on a time scale which would otherwise be inaccessible.

分子阳离子迁移和经历化学反应的能力将在各种不同的环境中确定，包括在室温下低粘度液体，77 K处的玻璃杯以及高粘性的低聚物和聚合物。聚合物要研究的范围从氯聚糖等叶绿聚合物到聚苯乙烯和聚乙烯。阳离子物种将通过暴露于蒽，萘和吡啶等多环状烃将产生，从Fabretron产生的高能辐射。将通过瞬时光谱法检测到产生的阳离子物种。除了对阳离子迁移速率的动力学分析外，还将在氧化硅固体和固液界面上研究吸收和表面结合的吡啶的荧光猝灭速率。表面对离心物产生的产生的影响也将由弥漫性反射率瞬态吸收光谱法确定。这些研究的结果将使人们更好地了解阳离子在表面上的反应以及有关有效淬火过程的因素。 %% %%来自有机动力学计划的这笔赠款支持巴黎圣母院大学的J. Kerry Thomas教授的持续工作。这些研究将针对理解表面对化学物质反应性的影响，并将提供关键数据，从而允许开发更有效的化学系统。调查将利用能够在不到十亿秒的时间内检测事件的设备。因此，可以在各种媒体中衡量带电物种的快速跳跃。使用快速荧光衰减过程的目标分子的使用提供了一种在时间尺度上监测化学过程的方法，否则该过程将是无法访问的。