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

这项来自化学合成（SYN）项目的研究奖支持明尼苏达大学的Lawrence Que教授对铁促进氧化过程的研究，这在生物学和工业环境中都很重要。深入了解大自然如何有效地进行强碳氢键的氧化，在设计大规模化学氧化催化剂方面发挥着重要作用，这些催化剂将更节能，更环保，更少浪费我们的资源。Que教授与许多来自不同背景的研究生和博士后密切合作，为他们成为下一代化学家中的领导者做好准备。该研究旨在合成高自旋（S = 2）铁(IV)-氧中间体的类似物，这些中间体是许多非血红素铁加氧酶的关键氧化剂。迄今为止所描述的绝大多数合成氧化铁（IV）配合物具有中间自旋（S = 1）， DFT计算预测其反应性远低于其高自旋对应物。为了验证DFT预测，我们将合成具有高自旋Fe(IV)=O单元的配合物，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，以便详细了解它们的几何和电子结构。高自旋配合物氧化底物C-H键的能力将与其性质相关，并与低自旋Fe=O配合物进行比较，以确定控制Fe=O反应性的因素。更好地了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.