Gated Electron Transfer in Copper(II)/(I) Systems

有了这个奖项，无机，生物无机和有机物 化学计划为合作研究项目提供支持 涉及大卫B医生Rorabacher和罗纳德R.施罗德 韦恩州立大学化学系教授和Leo A.奥克里莫维奇 威斯康星大学欧克莱尔分校化学系教授。 他们 将合成一系列硫醚铜、硫胺素、硫吡啶 其中铜（I）和铜（II）的氧化态均为 容易接近 研究的31个大环配体是 专门设计用于在内部施加不同类型的约束 配体骨架 利用循环伏安法、停流动力学、核磁共振 谱线增宽研究和选定的结构测定， 将研究配体几何变化与 在这些络合物中，电子转移到铜中心和从铜中心转移。 在某些条件下，在一个方向上的反应速率将是 “门控”的要求，中间体进行 构象变化分子力学计算将用于 比较反应过程中产生的反应中间体的能量， 电子转移步骤，并开发一些预测能力。 已知铜（I）和铜（II）的络合物具有不同的 几何形状，因此在氧化或还原时， 将发生构象变化。 构象变化产生了 电子转移的能垒。 如果这个能量屏障 控制，那么就有可能发生电子转移， 一个方向，就是要“走出去”。 这个话题很重要 目前对生物化学的兴趣，因为它可能是重要的， 金属蛋白的反应。 这项研究将有助于回答 关于在多大程度上构象变化的问题， 蛋白质或金属结合位点周围的蛋白质参与了天然的 系统，以及指出的方式来设计的具体催化剂。

With this award, the Inorganic, Bioinorganic, and Organometallic Chemistry Program provides support for a collaborative research project involving Drs. David B. Rorabacher and Ronald R. Schroeder of the Chemistry Department, Wayne State University, and Dr. Leo A. Ochrymowycz of the Chemistry Department, University of Wisconsin-Eau Claire. They will synthesize a series of copper thiaether, thiaamine, and thiapyridine complexes in which both copper (I) and copper(II) oxidation states are accessible. The thirty-one macrocyclic ligands targeted for study are specifically designed to impose differing types of constraints within the ligand framwork. Using cyclic voltammetry, stopped-flow kinetics, NMR line broadening studies, and selected structural determinations, they will investigate the relationship between ligand geometric changes and transfer of electrons to and from the copper centers in these complexes. Under some conditions, the rate of the reaction in one direction will be `gated` by the requirement for the intermediate to undergo a conformational change. Molecular mechanical calculations will be used to compare the energies of reaction intermediates generated during the electron transfer step and develop some predictive capability. Complexes of copper(I) and copper(II) are known to have different geometries, so that upon oxidation or reduction it is likely that conformational changes will occur. A conformational change creates an energy barrier to electron transfer. If this energy barrier can be controlled, then it becomes possible for electron transfer to occur in one direction, that is, to be `gated.` This topic is of considerable current interest in biological chemistry, because it may be important in the reactions of metalloproteins. This research will help answer questions about the extent to which conformational changes in the proteins or around the metal binding site are involved in natural systems, as well as point the way to design of specific catalysts.