PES/DFT STUDIES ON ELECTRONIC STRUCTURE CONTRIBUTIONS TO ELECTRON TRANSFER

电子结构对电子传输贡献的 PES/DFT 研究

• 批准号: 8169972
• 负责人: EDWARD I SOLOMON
• 金额: $ 1.63万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8169972
• 关键词: Biological Models; Complement; Complex; Computer Retrieval of Information on Scientific Projects Database; Cytochromes; Data; Electron Transport; Electronics; Ferredoxin; Funding; Grant; Heme; Institution; Kinetics; Ligands; Metalloproteins; Metals; Methodology; Methods; Modeling; Oxidation-Reduction; Pathway interactions; Process; Property; Relaxation; Research; Research Personnel; Resources; Roentgen Rays; Site; Source; Spectrum Analysis; Structure; Synchrotrons; United States National Institutes of Health; absorption; base; biological systems; density; electronic structure; high potential iron-sulfur protein; insight; metal complex; oxidation; research study; theories

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The major emphasis of our research is to apply variable energy photoelectron spectroscopy (PES) combined with X-ray absorption edge spectroscopy (XAS) to define electronic structure contributions to electron transfer (ET) in biological systems. PES provides a direct method to study inorganic redox processes and the contribution of electronic relaxation to redox properties (E¿, HAB, lambda). The shake-up satellite structure present in core and valence PES data can be used in combination with a valence bond configuration interaction (VBCI) model to experimentally quantify electronic relaxation (i.e. the change in electronic structure of metal complexes upon oxidation) and its contributions to reduction potentials and kinetics of ET. Variable-energy PES experiments provide a mechanism to maximize the metal while minimizing the ligand contributions to the valence band region through cross section effects (delayed maximum and Cooper minimum) and resonance enhancement. Our synchrotron-based studies on simple model systems [FeX4]2-/1 (X=Cl-, -SR) have afforded experimental results that define electronic structure and its changes upon redox. Complemented by density functional theory (DFT) calculations, these studies provide insight into electronic relaxation and allow extension to the metalloprotein sites. Using the methodology developed in the studies on [FeX4]2-/1, we are now examining model heme complexes. The data on the heme models combined with DFT calculations should also allow extention to and define the superexchange pathways for ET in the cytochromes. We will also extend these PES/DFT studies to [Fe4S4(SR)4] systems modeling the 4Fe ferredoxins and HiPIPs (high potential iron proteins), which will provide insight into electronic relaxation and its contributions to the kinetics and pathways for ET in the ferredoxins and HiPIPS.

该副本是使用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这是调查员的机构。 我们研究的主要重点是将可变的能量光电光谱（PES）与X射线抽象边缘光谱（XAS）结合使用，以在生物系统中定义对电子传输（ET）的电子结构贡献。 PE提供了一种直接研究无机氧化还原过程的方法，以及电子松弛对氧化还原性能的贡献（e e e e e，hab，lambda）。核心和价PES数据中存在的重塑卫星结构可与价值键合构相互作用（VBCI）模型结合使用，以实验量化电子弛豫（即氧化后金属复合物的电子结构的变化）及其对ET的还原电位和动力学的贡献。可变能量PES实验提供了一种使金属最大化的机制，同时通过横截面效应（延迟的最大值和最小库珀）和共振增强来最大程度地最大程度地减少对价带区域的配体贡献。我们对简单模型系统[FEX4] 2-/1（x = Cl-，-sr）的基于同步加速器的研究提供了定义电子结构及其在氧化还原上的变化的实验结果。这些研究通过密度功能理论（DFT）计算完成，提供了对电子松弛的见解​​，并允许向金属蛋白位点扩展。使用[Fex4] 2-/1的研究中开发的方法，我们现在正在研究模型血红素复合物。血红素模型与DFT计算相结合的数据还应允许扩展并定义细胞色素中ET的superexchange途径。我们还将将这些PES/DFT研究扩展到建模4FE铁蛋白和HIPIPS（高潜在铁蛋白）的[FE4S4（SR）4]系统，这些系统将深入了解电子松弛及其对养铁蛋白和HIPIPS中ET的动力学和途径的贡献。