RUI: Production of Highly Reactive Metal-Oxo Species with Molecular Oxygen and Visible Light for the Selective Oxidative Catalysis

有了化学系化学催化项目的这一奖项，西肯塔基大学(WKU)的张锐教授和他的学生将利用分子氧和可见光(阳光)，通过高价过渡金属氧物种开发可持续、“绿色”和选择性的氧化催化。所提出的光催化循环包括：1)可见光诱导金属(IV)大环二聚体的歧化生成金属(III)和金属(V)-氧氧化物种；2)底物被生成的活性金属(V)-氧物种氧化得到氧化产物和第二金属(III)物种；3)金属(III)络合物的有氧氧化以再生金属-氧代双核金属(IV)配合物。该方法将包括合成和鉴定用于高效光歧化反应的配体和金属(IV)二聚体类型，并通过阐明关键因素来优化催化条件。一个重要的目标是揭示所开发的光催化方法的反应范围。这项工作将解决全球重要的能源和环境问题。在氧化催化中使用分子氧和阳光而不需要外部共还原剂，对于实现将碳氢化合物转化为含氧酸盐的创新和经济有利的过程，同时走向对环境影响最小的“可持续化学”特别相关。这项工作还将深入了解支配光催化性能和过程的重要化学和结构因素。此外，它还将通过培训和教育西九龙大学的学生来整合研究和教育，西九龙大学主要是一所本科院校。这种跨学科的研究对学生非常有兴趣，并为他们提供了一个广泛的化学研究视角，这将促进学生作为新兴专业人员的学习和成功。这些学生中的许多人将在毕业后攻读博士学位。PI和研究团队在积极参与和培训本科生研究人员方面有着良好的记录。该项目还将接触到参加新成立的肯塔基州联邦住宅区数学和科学加顿学院的优秀理科学生，以及最近在化学系建立的5年制理学士/理科硕士课程。

With this award from the Chemical Catalysis Program in the Division of Chemistry, Prof. Rui Zhang and his students at the Western Kentucky University (WKU) will develop sustainable, "green" and selective oxidation catalysis via high-valent transition metal-oxo species using molecular oxygen and visible light (sunlight). The proposed photocatalytic cycle involves the following: 1) visible light-induced disproportionation of the mu-oxo metal(IV) macrocycle dimeric complex to form metal(III) and metal(V)-oxo oxidizing species; 2) substrate oxidation by the resulting reactive metal(V)-oxo species to give oxidized products and a second metal(III) species; concluding with 3) aerobic oxidation of the metal(III) complex to regenerate the mu-oxo dinuclear metal(IV) complex. The approach will include synthesis and identification of ligand and metal(IV) dimer types for efficient photo-disproportionation reactions and optimization of the catalytic conditions by elucidating key factors. An important goal will be to reveal the reaction scope of the developed photocatalytic methods. This work will address globally important energy and environmental issues. The use of molecular oxygen and sunlight without the need for an external co-reductant in oxidative catalysis is particularly relevant to realizing innovative and economically advantageous processes for conversion of hydrocarbons into oxygenates and, at the same time, to move toward a "sustainable chemistry" that has a minimal environmental impact. This work will also generate insight into important chemical and structural factors that govern photocatalytic properties and processes. Furthermore, it will integrate research and education through training and educating students at WKU, a primarily undergraduate institution. This interdisciplinary research is of significant interest to students and offers them a broad view of chemical research that will enhance student learning and success as emerging professionals. Many of these students will pursue doctorate degrees upon graduating. The PI and the research team have a strong record of actively involving and training undergraduate researchers. This project will also reach out to the exceptional science students attending the newly formed Commonwealth of Kentucky residential Math and Science Gatton Academy located on the campus of WKU as well as the recently established 5-year B.S./M.S. program in the Department of Chemistry.