High Reorganization Energy Electron Transfer Systems

有了这个奖项，有机和大分子化学项目支持威斯康星大学的斯蒂芬·尼尔森的研究，他将研究电荷局域对称价间（IV）化合物电子转移（ET）阳离子，这种阳离子在没有中间物的情况下通过分子两端之间的桥传递电子(Hy(+)- b -Hy(0) -Hy（0) - b -Hy(+)）。肼电荷承载单元（Hy）正在被“调谐”，以提供重组能和电子耦合的正确组合，使它们的ET速率常数处于ESR测量几种桥尺寸的正确范围内，从而允许对ET理论进行重要的测试。涉及以桥为中心的中间体(Hy(0) -B（+)-Hy(0)能量最小值）的“电子跳跃”显然与远距离移动电荷的生物ET反应有关，但目前还没有简单的IV模型化合物可用。具有不受限制的NN键旋转以最大化其重组能的Hy基团的系统应该产生电子跳变系统，即使对于小的对苯基桥也是如此。正在研究的其他系统在激发态而不是基态具有马库斯-赫什型两态图。例子包括中性化合物、双基分裂和电荷离域IV基离子。应用相当新的朱中村（ZN）理论来解释ET动力学测量似乎有希望更好地理解分子内和分子间ET实验。该奖项来自有机和大分子化学项目，支持威斯康星大学的斯蒂芬·尼尔森教授，他的研究认识到，理解电子转移反应对化学和生物学都至关重要，理解如何操纵电子相互作用是分子电子学发展领域的基础。从事这项工作的学生将接受特别广泛的训练，包括有机合成方法的合成，以及计算化学和包括电化学、核磁共振和ESR以及光谱学在内的物理测量。

With this award, the Organic and Macromolecular Chemistry Program supports Stephen Nelsen of the University of Wisconsin whose research will study charge localized symmetrical intervalence (IV) compound electron transfer (ET) cations that transfer an electron across a bridge between two ends of the molecule (Hy(+)-B-Hy(0) - Hy(0)-B-Hy(+)) without an intermediate. The hydrazine charge-bearing units (Hy) are being "tuned" to provide the right combination of reorganization energy and electronic coupling to put their ET rate constants in the correct range for measurement by ESR for several bridge sizes, allowing significant tests of ET theory. 'Electron hopping' that involves bridge-centered intermediates (Hy(0) -B(+)-Hy(0) an energy minimum ) is clearly involved in biological ET reactions that move charge over large distances, but no simple IV model compounds are yet available. Systems with Hy groups having NN bond rotation unrestricted to maximize their reorganization energy should generate electron-hopping systems, even for a small, p-phenylene bridge. Other systems are being studied that have a Marcus-Hush-type two-state diagram in their excited states instead of their ground states. Examples include neutral compounds, diradical diions and charge delocalized IV radical ions. Application of the rather new Zhu-Nakamura (ZN) theory to interpreting ET kinetic measurements appears promising for better understanding of both intramolecular and intermolecular ET experiments.This award from the Organic and Macromolecular Chemistry Program supports Professor Stephen Nelsen of the University of Wisconsin whose research recognizes that understanding electron transfer reactions is of fundamental importance to both chemistry and biology, and understanding how to manipulate electronic interactions is fundamental to the developing field of molecular electronics. Students trained doing this work will receive exceptionally broad training in organic synthetic methods in making their compounds, as well as in doing computational chemistry and making physical measurements involving electrochemistry, NMR and ESR, and optical spectroscopy.