Metal-Ligand and Metal-Metal Cooperativities as Design Principles for Base Metal Catalysis

在化学系化学催化项目的资助下，辛辛那提大学的关海荣博士正在开发用于合成有机分子的新型催化剂。催化反应在制造新药物和新材料、降低能源消耗、防止化学废物和利用可再生原料方面发挥着不可或缺的作用。贵金属，如Ru、Rh、Pd、Ir和铂常用于催化反应。然而，它们价格昂贵，供应有限，很难从化工产品中去除。为了开发更可持续的合成，正在努力使用贱金属，包括铁、钴、镍和铜，用于催化。困难在于，从这些金属中提取的催化剂通常活性较低，更容易分解。在这个项目中，关博士正在开发一种新型催化剂，这种催化剂具有金属和配体之间的协同性，或者说两种金属之间的协同性。有了这一策略，从廉价和丰富的金属中提取的催化剂更高效、更坚固，模仿了它们的贵金属类似物的反应活性。关博士为一门以催化为重点的本科实验室课程开发基于研究的教材。他还为STEM领域代表性不足的群体的学生提供研究机会，通过与当地化工行业的合作促进学生的专业发展。这项研究通过在先进化学制造、可再生能源和化学工业方面提供可持续创新，提高了国家福利。关博士正在开发新的策略，以设计具有类似贵金属催化剂反应活性的贱金属催化剂。合成了能够转移质子的三齿配体支撑的铁和铜配合物，并对醛、酮、酯、酰胺和二氧化碳(CO2)的催化加氢反应进行了测试。制备了铁-铜或铁-锌异双金属配合物，并将其用于催化水煤气变换反应条件下的还原反应。这些反应可能与工业有关，例如洗涤剂酒精的制造。催化剂还可能在二氧化碳转化和能量储存领域产生影响。为了更好地理解结构-反应关系，特别是配体和金属之间或两种金属之间的协同作用，人们进行了机理研究。为了支持该项目的更广泛影响，关博士积极参与了一些项目，重点是为代表不足的STEM学生提供研究机会，包括那些主要在本科院校和社区学院合作的学生。通过以研究为基础的教学和与当地公司的合作，关博士正在帮助学生发展他们的创造性和批判性思维技能，并促进他们的职业发展。该奖项反映了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。

With funding from the Chemical Catalysis Program of the Chemistry Division, Dr. Hairong Guan of the University of Cincinnati is developing new catalysts for the synthesis of organic molecules. Catalysis reactions play indispensable roles in making new drugs and novel materials, reducing energy consumption, preventing chemical waste, and utilizing renewable feedstocks. Precious metals such as ruthenium, rhodium, palladium, iridium, and platinum are often used in catalytic reactions. However, they are expensive, limited in supply, and difficult to remove from the chemical products. To develop more sustainable syntheses, efforts are being directed at using base metals, which include iron, cobalt, nickel and copper, for catalysis. The difficulty is that catalysts derived from these metals are usually less reactive and more prone to decomposition. In this project, Dr. Guan is developing new catalysts featuring cooperativity between a metal and a ligand, or cooperativity between two metals. With this strategy, catalysts derived from inexpensive and abundant metals are more efficient and robust, mimicking the reactivity of their precious metal analogs. Dr. Guan develops research-based educational materials for an undergraduate laboratory course focusing on catalysis. He also provides research opportunities to students from groups that are underrepresented in the STEM fields, enhancing student professional development through his collaborations with the local chemical industry. This research enhances national welfare, by providing sustainable innovation in advanced chemical manufacturing, renewable energy and chemical industry. Dr. Guan is developing new strategies to design base metal catalysts with reactivity akin to the precious metal catalysts. Iron and copper complexes supported by tridentate ligands capable of transferring protons are synthesized and tested for catalytic hydrogenation of aldehydes, ketones, esters, amides, and carbon dioxide (CO2). Heterobimetallic complexes of Fe-Cu or Fe-Zn are prepared and used to catalyze reduction reactions under water-gas shift reaction conditions. These reactions may be relevant to industry, for example manufacturing of detergent alcohols. The catalysts may also have impact in the areas of carbon dioxide conversion and energy storage. Mechanistic studies are carried out for a better understanding of structure-reactivity relationships, particularly the synergy between ligand and metal or between two metals. In support of the broader impacts of the project, Dr. Guan is actively engaged in programs focusing on providing research opportunities to underrepresented STEM students including those at collaborating primarily undergraduate institutions and community colleges. Through research-based teaching and collaborations with local companies, Dr. Guan is assisting students to develop their creative and critical thinking skills and facilitating their career development.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.