Reactive Intermediates and Reaction Mechanisms

涉及不稳定化学物质如多自由基和两性离子的形成和随后的反应活性的反应的基本动力学将被探讨。同时使用ESR， NMR和光学瞬态光谱将提供基本的机制信息，这将有助于从理性的角度设计涉及高活性中间体的化学反应。拟研究的课题包括：(1)二甲基氟烯及其相关试剂对氧烯丙基的捕集；(2)产生不连接的双基；(3)确定了四亚苯的自旋多重性和反应性；(4)基于断节四甲基的双基多元间隙的调整；(5)两个二亚甲基杂环通过苯环偶联合成多自由基；(6)稳定双自由基的合成与表征。这些化学系统将作为具有实际重要性的光学、导电和磁性质的材料的模型。这项来自有机动力学项目的资助支持耶鲁大学Jerome A. Berson教授的持续工作。伯森教授和他的研究小组将探索一种非常活跃的物质，叫做双自由基，它是在化学过程的中间阶段形成的，通常只存在几十亿分之一秒。有关这些中间体的信息可能使设计具有重要化学和技术特性的全新分子成为可能。从这项工作中得到的概念对于理解分子如何导电和光相互作用至关重要，也将有助于设计化学系统，该系统可用于制造光纤，以光脉冲的形式在长距离上更快、更有效地传输信息。

The basic kinetics of reactions which involve the formation and subsequent reactivity of unstable chemical species such as multiradicals and zwitterions will be probed. The concurrent use of ESR, NMR, and optical transient spectroscopy will provide basic mechanistic information which will aid in designing chemical reactions involving highly reactive intermediates from a rational viewpoint. The research topics to be investigated include: (1) the trapping of oxyallyls via dimethylfulvene and related agents; (2) production of disjointed biradicals; (3) confirmation of the spin multiplicity and reactivity of tetramethylene benzene; (4) adjustment of the multiplet gap of biradicals based upon disjointed tetramethyleneethanes; (5) synthesis of polyradicals based upon coupling of two dimethyleneheterocycles via a benzene ring; and (6) synthesis and characterization of stable biradicals. These chemical systems will serve as models for materials with optical, conducting, and magnetic properties of practical importance. %%% This grant from the Organic Dynamics Program supports the continuing work of Professor Jerome A. Berson at Yale University. Professor Berson and his research group will probe very reactive species, called diradicals, which are formed in the intermediate stages of chemical processes and often live for only a few billionths of a second. Information about these intermediates may make it possible design totally new molecules with important chemical and technical properties. The concepts to be derived from this work are critical to the understanding of how molecules conduct electricity and interact with light, and will also aid in the design of chemical systems which can be used to make optical fibers to transmit information in the form of light pulses faster and more efficiently over long distances.