X-RAY ABSORPTION STUDIES OF HEME AND NON-HEME IRON MODELS: APPLICATION TO BIOINO

血红素和非血红素铁模型的 X 射线吸收研究：在 BIOINO 中的应用

• 批准号: 7370498
• 负责人: KEITH O HODGSON
• 金额: $ 2.1万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7370498
• 关键词: RAY; ABSORPTION; STUDIES; HEME; NON

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. In studies performed during our previous proposals, a new methodology was developed for analyzing and interpreting iron L-edge transition intensity distributions in terms of the total and differential orbital covalency (DOC). It was found that the integrated iron L-edge intensity could be used to obtain the total covalency of the complex. Furthermore, a projection methodology was developed which allows the covalency of the individual symmetry-related sets of orbitals and the DOC to be experimentally determined from the L-edge multiplet intensity distribution. The previous study serves as a foundation for the series of studies proposed here. The methodology developed during the previous proposal will be expanded to complexes that exhibit metal-to-ligand charge transfer and complexes of non-cubic symmetry. The expanded methodology will be applied and calibrated to sigma-donor-pi-acceptor complexes, an essential step in the study of the nature of heme versus non-heme iron bonding and its relation to reactivity, a major focus of this proposal. Data will be obtained from a number of specific heme complexes and compared to the non-heme complexes of the previous study. Of special interest are the electronic structural differences amongst low-spin ferriheme systems of different ground state electronic configurations. Additionally, this proposed research will provide the groundwork for determining the electronic structure in a series of complexes that serve as models of the enzyme cytochrome c oxidase. The determination of covalency and DOC of these models should provide insight into the electronic structure of this enzyme and differences related to the O-O bond cleavage in the enzyme but not the model. Finally, the proposed research will begin our study of the electronic structure of high valent Fe-porphyrins. Using two non-heme iron(IV) complexes to define the electronic contributions of the Fe(IV) ion, we will next study the electronic structure of a recent Fe(IV)=O model compound.

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。在我们之前的研究中，发展了一种新的方法，用总轨道共价性和微分轨道共价性来分析和解释铁L边缘跃迁强度分布。结果表明，铁L边的积分强度可以用来计算络合物的总共价性。此外，还发展了一种投影方法，允许根据L边多重态强度分布实验确定单个对称性相关轨道集和DOC的共价性。前面的研究是本文提出的一系列研究的基础。在前面的提议中开发的方法将扩展到表现出金属到配体电荷转移的络合物和非立方对称的络合物。扩展的方法将应用和校准到sigma-给体-pi-受体络合物，这是研究血红素与非血红素铁键的性质及其与反应性的关系的关键一步，这是本提案的一个主要重点。数据将从一些特定的血红素复合体中获得，并与前一项研究的非血红素复合体进行比较。特别令人感兴趣的是不同基态电子组态的低自旋铁血红素系统之间的电子结构差异。此外，这项拟议的研究将为确定作为细胞色素C氧化酶模型的一系列络合物的电子结构提供基础。这些模型的共价性和DOC的测定应该能深入了解这种酶的电子结构以及与酶中O-O键断裂有关的差异，但不是模型。最后，提出的研究将开始我们对高价铁卟啉的电子结构的研究。使用两个非血红素铁(IV)络合物来定义Fe(IV)离子的电子贡献，接下来我们将研究最近一个Fe(IV)=O模型化合物的电子结构。