Visible Light and Divalent Lanthanides in Photoredox Catalysis

光氧化还原催化中的可见光和二价镧系元素

• 批准号: 1564755
• 负责人: Matthew Allen
• 金额: $ 40.5万
• 依托单位: Wayne State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-15 至 2020-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1564755&HistoricalAwards=false
• 关键词: Visible; Light; Divalent; Lanthanides; Photoredox

In this project funded by the Chemical Catalysis program of the Chemistry Division, Professor Matthew J. Allen, Chemistry Department, Wayne State University, is studying new lanthanide systems that catalytically perform reductions and bond-forming reactions when exposed to visible light. Catalysts are substances that permit chemical reactions to be run rapidly with minimum energy consumption. They are used in a variety of industrial processes. In this project, catalysts are being developed that utilize and can be switched on and off by visible light. In addition, they operate under conditions that are not compatible with current catalysts. Several important processes including reactions that form carbon-carbon bonds are studied. Graduate, undergraduate, and high school students are trained to become skilled and ethical scientists. High school students, who are from groups underrepresented in science, have an opportunity to participate in research, leading to a more educated and diverse scientific workforce.This project focuses on new lanthanide-containing complexes that can drive visible-light-promoted photoredox catalysis. Specifically, the project tests the hypothesis that if trivalent lanthanide-containing azacryptates are exposed to a sacrificial reductant and visible light, they perform catalysis at redox potentials more negative than divalent lanthanide salts alone. Testing this hypothesis simultaneously addresses two long-standing challenges in redox chemistry: (1) the need for photoredox catalyts tunable across a range of potentials and wavelengths for improved chemoselectivity and (2) the need for air-stable, non-toxic alternatives to samarium(II) hexamethyl phosphoramide. The research includes the synthesis of a series of complexes of divalent and trivalent europium and ytterbium. These complexes are characterized by UV/visible and fluorescence spectra, electrochemical potentials, thermodynamic and kinetic stabilities, crystal structures, solubilities, and propensities for transmetallation. Additionally, the complexes are studied with respect to their ability to catalyze important classes of photoredox reactions including reductions, carbon-carbon bond formations, and ring closures. Finally, students are trained in the scientific method and the responsible conduct of research.

在由化学部化学催化计划资助的该项目中，韦恩州立大学化学系教授Matthew J. Allen教授正在研究新的灯笼系统，这些系统在暴露于可见光时催化降低和粘结形成反应。催化剂是允许化学反应迅速运行的物质，并以最少的能耗运行。它们用于各种工业过程。在这个项目中，正在开发利用并可以通过可见光打开和关闭的催化剂。此外，它们在与当前催化剂不兼容的条件下运行。研究了一些重要的过程，包括形成碳键的反应。毕业生，本科和高中生接受培训，成为熟练和道德科学家。来自科学领域人数不足的小组的高中学生有机会参加研究，从而导致了受过教育和多样化的科学劳动力。该项目着重于含兰坦尼德的新综合体，可以推动可见光的光电photoreDox催化。具体而言，该项目检验了以下假设：如果三价含灯笼的azacryptates暴露于牺牲性还原和可见光下，则它们会在氧化还原电位上进行催化，而不是单独的二价灯笼盐。同时检验该假设，解决了氧化还原化学中的两个长期挑战：（1）需要在一系列电势和波长中可调节的光毒催化剂，以改善化学选择性，并且（2）需要空气稳定的，无毒的替代品（ii）甲酰胺基磷酸酰胺。这项研究包括合成一系列二价和三价欧洲裔和Ytterbium的复合物。这些复合物的特征在于紫外线/可见和荧光光谱，电化学电位，热力学和动力学稳定性，晶体结构，溶解度和跨金属的倾向。此外，研究了复合物，以催化重要类别的光毒反应类别的能力，包括减少，碳碳键形成和环闭合。最后，学生接受了科学方法和负责任的研究的培训。