Internal Redistribution of Energy in Chemicals Excited by Light

这笔有机化学和高分子化学的拨款为密歇根州立大学的彼得·瓦格纳博士的研究提供了支持。这项工作主要集中在各种有机化合物的光化学机理上。这些研究旨在阐明有机分子与光之间相互作用的细节。它们的理解对于许多化学和生物过程都很重要。一个分子的两个离散部分之间的化学相互作用是大多数现代合成有机反应的核心。许多这样的反应是由光的吸收独一无二地引发的。几个这样的光诱导反应是这项工作的主要主题。利用光来促进一个分子内的反应不仅允许一些其他方式不可能发生的新反应，而且还提供了对分子如何改变形状和各种化学反应所需的几何形状的独特见解。由于光激发分子的反应速度与分子改变形状的运动速度一样快，所以出现了用热化学无法测量的全新的竞争。将研究几个体系，在这些体系中，一个分子中两个活性成分的取向可以改变，以便评估这种取向对特定反应的影响。要研究的反应包括激发能转移；电子转移，有时是化学键和新产物的形成；氢原子转移，然后是新产物的形成；以及卤素原子的裂解产生聚合引发剂。

This grant in Organic and Macromolecular Chemistry provides support for the research of Dr. Peter Wagner, Michigan State University. The work is focused on photochemical mechanisms of a variety of organic compounds. These studies are designed to elucidate the details of the interactions between organic molecules and light. Their understanding is important for a number of chemical and biological processes. Chemical interactions between two discrete parts of one molecule are at the core of most modern synthetic organic reactions. Many such reactions are initiated uniquely by the absorption of light. Several such light-induced reactions are the main subject of this work. The use of light to promote reactions within one molecule not only allows some new reactions that could not otherwise occur, but also provides unique insight into how molecules change shape and into the geometries required for various chemical reactions. Because the reactions of light-excited molecules are as fast as the motions by which molecules change their shapes, altogether new competitions occur that cannot be measured in thermal chemistry. Several systems will be studied in which the orientation of the two reactive components in one molecule can be varied so that the effect of such orientation on specific reactions can be assessed. The reactions to be studied include transfer of excitation energy; electron transfer, sometimes followed by chemical bonding and novel product formation; hydrogen atom transfer, followed by novel product formation; and cleavage of halogen atoms to produce polymerization initiators.