CAREER: Main-Group Element Catalysis Enabled with Outer Functional Spheres of Molecular Catalysts

在化学系化学催化项目的资助下，辛辛那提大学的江教授将创造出用于二氧化碳还原和有机卤化物脱卤化的无金属催化剂。开发廉价和耐用的催化剂是朝着高效生产化学品和修复环境污染物迈出的重要一步。传统上，由于稀有元素的高反应性，制备小分子转化催化剂时使用昂贵的稀有元素，但这些体系存在毒性低、丰度低、成本高等问题。在本项目中，将通过改变催化活性中心周围的分子环境来提高催化活性。江教授将积极吸引科学、技术、工程和数学(STEM)学科中人数较少的学生和普通公众参加以可持续发展化学为重点的外展活动。此外，江教授的团队将开发和维护一个互动的开源网站，用于波脚分析，这是一种评估电催化剂性能的强大技术。该网站的建设工作即将启动，并将整合到江教授的研究网站中，方便社会各界访问。这项研究的结果将有助于实现二氧化碳和卤化污染物等丰富的小分子向附加值产品的能效转化，这对我们的社会既具有科学挑战性又具有重要的战略意义。该项目将探索欠发达的主族元素催化，旨在就结构柔性、pKA和外部功能球的大小在定制的三维分子结构的催化活性中的作用提供机理见解和合理的设计框架。建议的研究重点是使用具有氧化还原活性的双功能配体和外部功能球来弥补主族元素缺乏外层d轨道的事实。具体地说，将设计、合成和评估使用具有不同外部功能球体的卟啉配体的Group15基催化剂，以减少二氧化碳和有机卤化物脱卤化。将主族元素基催化剂的催化性能与目前过渡金属基催化剂的催化性能进行比较。结合基于溶液和表面的技术，结合密度泛函理论计算，将被用于识别反应中间体并帮助阐明催化机理。这项研究旨在丰富人们对氧化还原活性配体与外部功能球和15族元素之间的相互作用如何被用作键激活的策略，以及如何使用具有外部功能球的配体能够实现第15族元素催化的理解。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 in the Division of Chemistry, Professor Jiang of the University of Cincinnati will create metal-free catalysts for carbon dioxide reduction and organohalide dehalogenation. The development of inexpensive and robust catalysts is an important step towards efficient production of chemicals and remediation of environmental pollutants. Traditionally, expensive and rare elements are employed to prepare the catalysts for small molecule conversion due to the high reactivity of the rare elements; however, these systems suffer from toxicity, low abundance, and high cost. In this project, the catalytic activity will be enhanced through the modification of molecular environment around the catalytic active site. Professor Jiang will actively engage a diverse group of underrepresented students in science, technology, engineering and mathematics (STEM) disciplines and the general public in outreach activities focused on chemistry of sustainability. In addition, Professor Jiang's group will develop and maintain an interactive, open-source website for foot-of-the-wave analysis, a powerful technique for evaluating the performance of electrocatalysts. The construction of the website will start soon and be integrated into Professor Jiang's research website for easy access by the community. The results of the proposed research will contribute to the achievement of energy-efficient conversion of abundant small molecules such as carbon dioxide and halogenated pollutants into value-added products, which is both scientifically challenging and strategically important for our society.This project will explore under-developed main-group element catalysis and aims to provide both mechanistic insight and a rational design framework concerning the roles of structural flexibility, pKa, and the size of outer functional spheres in the catalytic activity of tailored 3-dimensional molecular architectures. The proposed study focuses on using bifunctional ligands with redox activity along with outer functional spheres to compensate for the fact that main-group elements lack outer shell d-orbitals. Specifically, Group15-based catalysts using porphyrin ligands with a diverse set of outer functional spheres will be designed, synthesized, and evaluated for carbon dioxide reduction and organohalide dehalogenation. The catalytic performance of the main-group element-based catalysts will be compared to current transition metal-based counterparts. A combination of solution- and surface-based techniques, in conjunction with density-functional theory calculations, will be used to identify reaction intermediates and help elucidate the catalytic mechanism. This research seeks to enrich the understanding of how interactions between redox-active ligands with outer functional spheres and Group 15 elements can be used as a strategy for bond activation, and how the use of a ligand with an outer functional sphere enables Group 15 element catalysis.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.