High Reorganization Energy Electron Transfer Systems

有了这个奖项，有机和大分子化学计划支持威斯康星州的大学的斯蒂芬·尼尔森，其研究将研究电荷局部对称的间隔（IV）化合物电子转移（ET）阳离子，转移电子通过分子两端之间的桥梁（Hy（+）-B-Hy（0）- Hy（0）-B-Hy（+））没有中间体。肼电荷承载单元（Hy）正在被“调整”，以提供重组能量和电子耦合的正确组合，从而将其ET速率常数置于正确的范围内，以便通过ESR测量几种桥尺寸，从而对ET理论进行重大测试。涉及桥中心中间体（Hy（0）-B（+）-Hy（0）能量最小值）的“电子跳跃”显然涉及在大距离上移动电荷的生物ET反应，但是还没有简单的IV模型化合物可用。具有NN键旋转不受限制以最大化其重组能量的Hy基团的系统应产生电子跳跃系统，即使对于小的对亚苯基桥。正在研究的其他系统在其激发态而不是基态具有马库斯-库什型双态图。实例包括中性化合物、双自由基二离子和电荷离域IV自由基离子。应用较新的Zhu-Nakamura（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的ET实验。这一奖项来自有机和大分子化学计划，支持威斯康星州大学的Stephen Nelsen教授的研究，他的研究认识到理解电子转移反应对化学和生物学都具有根本的重要性，了解如何操控电子相互作用是发展中的分子电子学领域的基础。接受过这项工作培训的学生将在有机合成方法方面接受非常广泛的培训，以制造他们的化合物，以及进行计算化学和进行涉及电化学，NMR和ESR以及光谱学的物理测量。

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.