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

有机化合物与空气中的氧气在催化剂作用下的反应是每天大规模进行的最重要的过程之一，用于生产有价值的化学品、修复污染物和生产能源。在这个项目中，西肯塔基大学的张锐博士和他的学生们正在设计高效的催化剂，这种催化剂可以利用阳光激活大气中的氧气，并将其转移到廉价材料中，用于生产高价值的商品化学品。使用太阳能和大气氧气而不是化学试剂来氧化散装化学品更可持续，产生的化学废物更少，并有可能降低经济成本。这项研究对绿色化学的基础科学和技术产生了影响。该项目为参与的科学、技术、工程和数学(STEM)学科的本科生提供尖端研究经验，从而培养未来的STEM专业人员。来自加顿学院的高中生也在实验室里学习催化研究。加顿学院是西肯塔基大学的住宅区数学与科学学院，他们也在实验室里学习催化研究。通过化学催化项目获得这个奖项，西肯塔基大学的张睿博士和他的学生正在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。这方面的研究已经证明了一系列氧代双卟啉和氧代腐蚀剂作为有用的光催化剂具有独特的反应活性。它们可用于通过歧化反应生成高价过渡金属氧物种的氧化反应。Salen基催化剂被认为是最成功和应用最广泛的催化体系之一。然而，到目前为止，对这些Salen体系的机理研究一直受到这样一个事实的阻碍，即催化活性物种仅作为短暂的假定中间体出现。现在，张教授正在探索新的方法来生产和阐明Salen-金属-氧代氧化物种，这是一项具有挑战性的任务。人们正在合成和研究各种含有光吸收基团的金属-Salen络合物，以努力捕捉广谱的光。这项工作的发现扩大了金属-氧化学的范围，并探索了Salen-金属-氧配合物的反应模式。更重要的是，一系列带有捕光单元的氧代双金属SALENS的合成和研究正在引领着用于重要的有氧氧化反应的新一代光催化剂的出现。此外，这一奖项使张睿博士能够保持强大的本科生研究计划，积极吸引STEM学生参与研究项目的各个阶段。这有效地为他们作为未来的STEM专业人员做好了准备。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The reaction of organic compounds with the oxygen in air with a catalyst is one of most important processes conducted daily on a large scale for the production of valuable chemicals, remediation of pollutants, and the production of energy. In this project, Dr. Rui Zhang and his students at Western Kentucky University (WKU) are designing efficient catalysts that can use sunlight to activate the atmospheric oxygen and transfer it to inexpensive materials for production of high-value commodity chemicals. The use of solar energy and atmospheric oxygen rather than a chemical reagent in oxidation of bulk chemicals is more sustainable, generates less chemical waste, and potentially reduces economic costs. This research impacts the fundamental science and technology of green chemistry. The project is providing cutting-edge research experiences for the participating undergraduate students in science, technology, engineering and mathematics (STEM) disciplines and thereby training future STEM professionals. High school students from the Gatton Academy, the residential Math and Science Academy located on WKU's campus, are also spending time in the laboratory and learning about catalysis research.With this award through the Chemical Catalysis Program, Dr. Rui Zhang and his students at Western Kentucky University are developing sustainable, "green" and selective oxidation catalysis via high-valent transition metal-oxo species, using molecular oxygen and visible light (sunlight). Prior studies in this area have demonstrated the unique reactivity of a series of oxo bisporphyrins and oxo corroles as useful photocatalysts. They can be used for oxidations in which high-valent transition metal-oxo species are produced through a disproportionation reaction. The salen-based catalysts are accepted as one of the most successful and widely applicable catalytic systems. However, mechanistic studies on these salen systems have so far been hampered by the fact that the catalytically active species appear only as fleeting putative intermediates. Now Prof. Zhang is exploring new ways to produce and elucidate the salen-metal-oxo oxidizing species, a challenging task. A variety of metal-salen complexes that contain photo-absorbing groups are being synthesized and investigated in an effort to capture a broad spectrum of light. The findings from this work are extending the scope of metal-oxo chemistry and exploring reactivity patterns of salen-metal-oxo complexes. More importantly, the synthesis and study of a series of oxo bis-metal-salens with attached light-harvesting units are leading to the new generation of photocatalysts for important aerobic oxidations. In addition, this award enables Dr. Rui Zhang to maintain a strong undergraduate research program, actively engage STEM students in all stages of the research projects. This effectively prepares them as future STEM professionals.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.