Fundamental Studies of Electron Transfer in Supramolecular Systems

大卫教授H.匹兹堡大学化学系的沃尔德克因其对超分子体系中电子转移的研究而得到有机和大分子化学项目的支持。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诱导电子转移。这些研究将探索对化学反应性和超分子化学很重要的溶剂化和电子耦合的基本问题。通过研究在刚性单分子系统中的电子转移，该系统在分子裂缝的相对侧上具有电子供体和受体单元，可以评估供体和受体基团的电子云与其他分子之间的非键合接触的重要性。研究将进行两种类型的系统，其中一个分子部分是共价结合到刚性桥，并位于裂缝和一个客体分子氢键位于桥上的受体。分子溶剂化模型，耦合对电子性质的依赖，从弱到强耦合的转变，以及核运动的影响将被探索。不同分子单元之间的电子转移是许多自然（例如，光合作用）和技术（例如，腐蚀）过程。此外，电子转移是一种相对简单的化学转化，可以进行严格的定量研究。在更广泛的层面上，电子转移和电荷位移是大多数化学反应的核心要素。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，这是任何化学转化的基本要素，还没有得到很好的理解。在有机和高分子化学项目的支持下，大卫H.匹兹堡大学化学系的沃尔德克正在进行研究，旨在调查和量化电子转移反应的基本方面，这些反应涉及电子通过非键合接触的隧穿。

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.