High-Valent Nonheme Iron-Oxo Complexes: Synthesis and Reactivity

该项目由化学部化学合成计划资助。明尼苏达大学的劳伦斯·奎教授准备了一种铁化合物，这种化合物模仿生物分子，将通常不活跃的物种转化为更有用的物种。一个例子是将天然气中的主要成分甲烷转化为甲醇，这是一种重要的工业原料。由于生物系统的存在只是昙花一现，所以研究它们非常困难。在这个项目中制备的模型化合物被设计成比生物化合物更稳定。额外的稳定性使我们能够研究生物系统到底是如何运作的。这不仅揭示了基本的生化信息，还允许为工业和环境应用中的困难反应设计“生物启发”催化剂。此外，该项目还在多学科背景下培养研究生。这些学生所接受的培训和发展对于培养能够在全球市场上竞争的下一代国内科技人才至关重要。这项研究的主要目标是产生能够激活氧气的单核非血红素铁酶的合成类似物。为了实现这一目标，我们合成了双自旋Fe(IV)=O和Fe(V)=O的配合物，并用X射线单晶和光谱方法进行了表征，包括EPR、穆斯堡尔谱、共振拉曼光谱、核磁共振光谱和X射线吸收光谱。这些方法提供了对该复合体的几何和电子结构的详细了解。这些信息被用来理解控制高价铁氧中心反应性的电子因素。这些结果对C-H键氧化催化剂的开发具有指导意义。该项目为研究生提供培训，要求他们获得合成、设计、光谱学、动力学和机理方面的专业知识，并根据相关的生物化学和计算研究来解释这些结果。

This project is funded by the Chemical Synthesis program of the Chemistry Division. Professor Lawrence Que of the University of Minnesota prepares iron compounds that mimic biological molecules that convert normally unreactive species to more useful ones. An example is the conversion of methane, the main component in natural gas, to methyl alcohol, an industrially important feedstock. Since the biological systems have only fleeting existence, they are very difficult to study. The model compounds prepared in this project are designed to be more stable than the biological ones. The additional stability permits an investigation of exactly how the biological systems function. This not only reveals basic biochemical information, but also allows the design of "bio-inspired" catalysts for difficult reactions with industrial and environmental applications. Additionally, the project educates graduate students in a multidisciplinary context. The training and development that these students receive is critically important for preparing the next generation of domestic science and technology personnel capable of competing in the global marketplace. The primary goal of the research is to generate synthetic analogs of the mononuclear nonheme iron enzymes that activate oxygen. Toward this goal complexes of doublet spin Fe(IV)=O and Fe(V)=O are prepared and characterized by X-ray crystallography and spectroscopic methods including EPR, Mössbauer, resonance Raman, NMR, and X-ray absorption. These methods provide a detailed insight into the geometric and electronic structures of the complex. This information is used to understand the electronic factors that govern the reactivity of a high-valent iron-oxo center. The results guide the development of catalysts for the oxidations of C-H bonds. This project provides training for graduate students and requires them to gain expertise in synthesis, design, spectroscopy, kinetics and mechanism, and to interpret these results in light of related biochemical and computational studies.