Fundamental Studies of Electron Transfer in Supramolecular Systems

匹兹堡大学化学系的戴维·H·沃尔德克教授因研究超分子体系中的电子转移而得到有机化学和高分子化学计划的支持。时间分辨荧光光谱将被用来研究明确定义的超分子体系中的光致电子转移。这些研究将探索溶剂化和电子耦合的基本问题，这些问题对化学反应和超分子化学很重要。通过研究刚性单分子体系中的电子转移，在分子裂隙的两侧具有电子给体和受体单元，可以评估给体和受体基团的电子云与其他分子之间非键接触的重要性。将对两种类型的系统进行研究，一种是分子部分共价结合到刚性桥上并位于裂隙中，另一种是客体分子氢键连接到位于桥上的受体。将探讨分子溶剂化模型、耦合对电子性质的依赖、从弱耦合到强耦合的转变以及核运动的影响。不同分子单元之间的电子转移是许多自然(如光合作用)和技术(如腐蚀)过程中的主要事件。此外，电子转移是一种相对简单的化学转换，可以进行严格的定量研究。在更广泛的层面上，电子转移和电荷置换是大多数化学反应的中心元素。尽管如此，我们对非键合分子的两个电子云如何相互作用的理解还不是很清楚，这是任何化学转化的基本元素。在有机化学和高分子化学项目的支持下，匹兹堡大学化学系的戴维·H·沃尔德克教授正在进行旨在调查和量化电子转移反应的基本方面的研究，这些反应涉及电子通过非键接触的隧道传输。

Professor David H. Waldeck, of the Department of Chemistry at the University of Pittsburgh, is supported by the Organic and Macromolecular Chemistry Program for his studies of electron transfer in supramolecular systems. Time-resolved fluorescence spectroscopy will be used to study photoinduced electron transfer in well-defined supramolecular systems. The studies will explore fundamental issues of solvation and electronic coupling that are important to chemical reactivity and supramolecular chemistry. By studying electron transfer in a rigid unimolecular system which has electron donor and acceptor units on opposite sides of a molecular cleft, the importance of non-bonded contacts between the electron clouds of the donor and acceptor groups and other molecules can be assessed. Studies will be performed for two types of systems, one in which a molecular moiety is covalently bound to the rigid bridge and lies in the cleft and one in which a guest molecule hydrogen bonds to a receptor located on the bridge. Molecular solvation models, the dependence of coupling on electronic character, the transition from weak to strong coupling, and the influence of nuclear motion will be explored.Electron transfer between distinct molecular units is the primary event in many natural (e.g., photosynthesis) and technological (e.g., corrosion) processes. In addition, electron transfer is a relatively simple chemical transformation amenable to rigorous and quantitative study. On a broader level, electron transfer and charge displacement are central elements of most chemical reactions. Nonetheless, our understanding of how the two electron clouds of non-bonded molecules interact with one another, an essential element of any chemical transformation, is not well understood. With the support of the Organic and Macromolecular Chemistry Program, Professor David H. Waldeck, of the Department of Chemistry at the University of Pittsburgh, is carrying out studies designed to investigate and quantify fundamental aspects of electron transfer reactions that involve electron tunneling through non-bonded contacts.