DETERMINATION OF ELECTRONIC AND GEOMETRIC STRUCTURES OF NOVEL FE-S SYSTEMS

新型 FE-S 系统的电子和几何结构的确定

• 批准号: 8170324
• 负责人: Robert Karoly Szilagyi
• 金额: $ 0.03万
• 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/8170324
• 关键词: Area; Astrobiology; Behavior; Capsid; Charge; Collection; Computer Retrieval of Information on Scientific Projects Database; Data; Development; Electronics; Funding; Gases; Grant; Hydrogen; Institutes; Institution; Investigation; Ions; Iron; Length; Ligands; Maps; Metabolic; Metals; Methods; Minerals; Nuclear; Phase; Plasma; Preparation; Proteins; Research; Research Personnel; Research Support; Resources; Role; Source; Structure; Sulfur; Surface; System; Temperature; Time; United States National Aeronautics and Space Administration; United States National Institutes of Health; Viral; absorption; beamline; catalyst; insight; nanometer; nanoparticle; novel; programs; protein structure; research study; small molecule

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. Multi-edge x-ray absorption spectroscopic investigations of modified Fe-S mineral surfaces and nanoparticles are proposed in order to map the Fe-S phase diagrams as a function of length scale (micrometer vs. nanometer), synthesis (surface/beam, protein-cage controlled synthesis), and preparation conditions (exposure time, temperature, pH, presence of other ions). We hypothesize that using energy- (surface/beam) and structure- (protein cage or viral capsid) controlled synthesis of Fe-S systems, areas of Fe-S phase diagrams can be accessed that would not be possible by conventional synthetic methods. Recently obtained preliminary data already indicate the existence of a previously unobserved reduced state of pyrite, which was prepared by exposing pristine [100] pyrite surface to hydrogen atom/hydrogen gas plasma. We will take advantage of the complementarity of XAS data at the Fe K-edge, Fe L-edge, and S K-edge. Recent beamline development at BL4-3 now allows for collection of sulfur EXAFS, which in combination with iron EXAFS can provide more reliable fits of geometric structure for hard to characterize intermediates or transition states. XANES analysis of preedge and rising-edge features of Fe L-edge and S K-edge spectra provides electronic structural information about effective nuclear charges of metal/ligand centers, orbital compositions, ligand-field splitting of metal centers, and non-innocent behavior of ligands. Structural insights from the proposed experiments have an impact on the role of Fe-S systems as pre-biotic metabolic catalysts (NASA Astrobiology Institute supported research program at MSU), as well as, potential in proposing novel industrial catalysts from abundant Fe-S containing materials for activation of small molecules such as dinitrogen or dihydrogen.

该副本是利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，这不一定是调查员的机构。 提出了对修饰的Fe-s矿物表面和纳米颗粒的多边缘X射线吸收光谱研究，以绘制Fe-S相图作为长度尺度（微米与纳米尺），合成（表面/束，蛋白质型对照合成）的函数，并映射Fe-S矿物表面和纳米颗粒。我们假设使用能量（表面/束）和结构 - （蛋白质笼或病毒式衣壳）受控的Fe-S系统的合成，可以访问Fe-S相图的面积，而传统合成方法则无法使用。最近获得的初步数据已经表明存在先前未观察到的黄铁矿状态，该状态是通过将原始的黄铁矿表面暴露于氢原子/氢气等离子体中来制备的。我们将利用Fe K-Edge，Fe L-Edge和S K-Edge的XAS数据的互补性。现在，BL4-3处的光束线发育允许收集硫Exafs，与铁EXAF结合使用可以提供更可靠的几何结构拟合，以使难以表征中间体或过渡状态。 Fe l-Edge和S K-Edge光谱的较前和上升特征的XANES分析提供了有关金属/配体中心的有效核电，轨道组成，金属中心的配体场分裂以及配体行为的非企业行为的电子结构信息。提出的实验的结构见解会影响Fe-S系统作为Biotigic代谢催化剂（NASA天文学研究所支持MSU的研究计划）的作用，以及在提出新型的工业催化剂中，从含有丰富的Fe-S的新型工业催化剂中，含有丰富的小分子的材料，例如激活小分子，例如恐龙型或二氢或二氢或二氮。