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

有了这个奖项，无机、生物无机和有机金属化学项目为包括博士在内的合作研究项目提供了支持。韦恩州立大学化学系的David B. Rorabacher和Ronald R. Schroeder，以及威斯康星大学欧克莱尔分校化学系的Leo A. Ochrymowycz博士。他们将合成一系列铜硫醚、硫胺素和硫吡啶配合物，其中铜(I)和铜（II）氧化态都可达到。利用循环伏安法、停止流动动力学、核磁共振谱线拓宽研究和选择的结构测定，他们将研究这些配合物中配体几何变化和电子从铜中心转移之间的关系。预期在某些条件下，一个方向上的反应速率将由中间体发生构象变化的要求“门控”。已知铜(I)和铜（II）的配合物具有不同的几何形状，因此在氧化或还原时可能会发生构象变化。构象变化产生了电子转移的能量垒。如果这个能量势垒可以被控制，那么电子转移就有可能发生在一个方向上，也就是说，被“门控”。这一课题在生物化学领域引起了广泛的关注，因为它可能在金属蛋白的反应中具有重要意义。这项研究将有助于回答有关蛋白质或金属结合位点周围的构象变化在多大程度上参与这种作用的问题。

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. 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. It is expected that 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. %%% 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 to answer questions about the extent to which conformational changes in the proteins or around the metal binding site are involved in this effect.