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

这项来自化学合成（SYN）计划的研究奖支持明尼苏达大学的Lawrence Que教授研究在生物学和工业环境中重要的铁促进氧化过程的工作。深入了解大自然如何有效地进行强C-H键的氧化，在设计用于大规模化学的氧化催化剂方面发挥着重要作用，这些催化剂将更加节能，更加环保，并且减少对我们资源的浪费。Que教授与来自不同背景的研究生和博士后同事密切合作，为他们成为下一代化学家的领导者做准备。拟议的研究旨在生成高自旋（S = 2）铁（IV）-氧代中间体的合成类似物，这些中间体作为许多非血红素铁加氧酶的关键氧化剂。迄今为止描述的绝大多数合成氧代铁（IV）络合物具有中间自旋（S = 1），DFT计算预测其反应性比其高自旋对应物低得多。为了测试DFT预测，我们将合成具有高自旋Fe（IV）=O单元的复合物，并尽可能通过X射线晶体学和光谱方法的组合来表征它们，以详细了解它们的几何和电子结构。高自旋络合物氧化衬底C-H键的能力将与它们的性质相关，并与低自旋Fe=O络合物的性质进行比较，以确定哪些因素控制Fe=O反应性。更好地理解这些因素对于开发更有效的C-H键氧化催化剂将是重要的。

This research award from the Chemical Synthesis (SYN) program supports work by Professor Lawrence Que of the University of Minnesota to study iron facilitated oxidation processes that are important in biology and in industrial settings. Gaining insights into how Nature carries out the oxidation of strong C-H bonds efficiently plays an important role in the design of oxidation catalysts for large scale chemistry that will be more energy efficient, more environmentally friendly, and less wasteful of our resources. Professor Que is working closely with many graduate students and postdoctoral associates from diverse backgrounds and preparing them to become the leaders among the next generation of chemists.The proposed research aims to generate synthetic analogs of high-spin (S = 2) iron(IV)-oxo intermediates that serve as the key oxidants for many nonheme iron oxygenases. The vast majority of synthetic oxoiron(IV) complexes described to date have intermediate spin (S = 1), which DFT calculations predict to be much less reactive than their high-spin counterparts. To test the DFT prediction, we will synthesize complexes with high-spin Fe(IV)=O units and characterize them by X-ray crystallography whenever possible and by a combination of spectroscopic methods in order to gain detailed insight into their geometric and electronic structures. The abilities of the high-spin complexes to oxidize substrate C-H bonds will be correlated with their properties and compared to those of low-spin Fe=O complexes to determine what factors control Fe=O reactivity. A greater understanding of such factors will be important for the development of more effective C-H bond oxidation catalysts.