Photoactivation of Distal Groups in Polyfunctional Molecules

有机和高分子化学项目的资助 支持研究光诱导化学的机制， 反应. 莫里森博士在光化学反应的重点是 紧密的，但形式上非共轭的官能团的相互作用 在光产生的激发态中相互作用的基团 吸收 这种系统作为许多国家的模型是重要的。 生命过程的光诱导化学序列。 在 光合作用，例如，叶绿素中的一个“天线”组 收集光能，然后将其转移到附近的 “受体”启动化学变化。 双功能分子的光化学反应可以广泛地 （a）涉及键之间的形成， 两种功能，以及（B）主要仅涉及一种功能的那些 在两个基团中，非反应部分则充当 “天线”来收集光子。 在后一种情况下， 现在认识到可以导致激活 远端反应组 反应基团可以是 在紫外光谱中相对透明（例如 氯、乙氧羰基和烯烃取代基），或者本身 能够吸收（例如，酮），但仍然 可能被atenna选择性激活。 本研究 主要针对“B类”系统。 根本问题 问题的答案包括：（1）一般性如何， 什么是立体电子学的限制， 激活远端功能;（2）这些现象是如何 综合利用;（3）它们如何反映在 复杂分子的光稳定性？ 作为先前由基金会资助的研究的一个延伸， 授予CHE-8318825，莫里森博士还启动了研究 涉及光化学中的金属离子催化， 气相中的光化学 这两个项目都揭示了 新的和有趣的化学，其延伸是 包括在本方案中。

This grant in the Organic and Macromolecular Chemistry Program supports research on the mechanisms of light-induced chemical reactions. Dr. Morrison's focus in photochemical reactions is the interaction of close, but formally non-conjugated functional groups which interact in the excited states generated by light absorption. Such systems are important as models for many of the light-induced chemical sequences of life processes. In photosynthesis, for example, one "antenna" group in chlorophyll harvests light energy and then transfers it to a nearby "receptor" for initiating chemical changes. Photochemical reactions of bifunctional molecules can be broadly subclassified into those (a) involving bond formation between the two functionalities, and (b) those primarily involving only one of the two groups, the non-reacting moiety then serving as an "antenna" to harvest photons. In the latter case, a variety of mechanisms are now recognized which can lead to activation of the distal, reacting group. The reacting group may either be relatively transparent in the ultraviolet spectrum (examples are chlorine, carbethoxy, and alkene substituents), or be itself capable of asborption (a ketone, for example), but still potentially selectively activated by the atenna. This research is primarily addressed to "Class b" systems. The basic questions for which answers are sought include: (1) How general, and with what stereoelectronic limitations, are the various mechanisms for activiting distal functionalities; (2) How may these phenomena be utilized synthetically; and (3) How are they reflected in the photostability of complex molecules? As an out growth of research previously supported by Foundation Grant CHE-8318825, Dr. Morrison has also initiated studies involving metal ion catalysis in photochemistry and photochemistry in the gas phase. Both projects have uncovered new and intriguing chemistry, the extensions of which are included in the present program.