Hyperpolarization Catalysts for in situ Mechanistic Studies

在化学部门化学合成项目的资助下，伊利诺伊大学香槟分校化学系的Alison Fout将开发新的钴基化合物，这种化合物可以促进重要化学过程中氢的反应。氢是一种极为重要的化学原料，广泛用于各种化学过程。然而，它本身不反应或反应很慢。为了解决这个问题，人们开发了一些金属化合物，它们可以激活氢，并大大加快氢的反应速度。这些化合物被称为催化剂，几乎都是基于昂贵的稀有金属。这个项目研究的是一种较便宜的金属钴活化氢的能力。由于氢如何加入各种化合物的细节很难确定，因此在这项研究中，将使用一种称为对氢的不寻常形式的氢，将测量的灵敏度提高到20万倍。此外，该项目旨在提高下一代科学家的多样性、公平性和包容性。富特教授和她的学生将参加旨在为弱势群体的本科生提供研究经验的3M暑期学者计划、面向农村学校小学生的下一代伊利诺伊州科学家计划，以及面向6-8年级女孩的“女生亲密训练营”。本项目合成钴配合物，可作为对氢诱导极化（PHIP）催化剂。这要求抗磁性配合物在直接和间接超极化的整个催化循环中保持S=0。为了实现这一目标并获得Co(I)/Co（III）催化循环，制备了含有富电子部分和碳烯的配体配合物。它们催化PHIP的活性在一系列底物上进行了评估，包括烯烃、炔烃和芳烃，它们的官能团中具有长弛豫核。有些底物是聚合催化的关键反应物。在这些情况下，PHIP效应被用于检测和研究以前未观察到的机械中间体。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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 Synthesis Program in the Chemistry Division, Alison Fout in the Department of Chemistry at the University of Illinois Urbana-Champaign, will develop new cobalt-based compounds that can facilitate the reactions of hydrogen in important chemical processes. Hydrogen is an extremely important chemical feedstock that is used a wide variety of chemical processes. However, by itself it does not react or reacts very slowly. To circumvent this problem a number of metal compounds have been developed that activate hydrogen and greatly speed its rate of reactions. These compounds are called catalysts and almost all are based on expensive, rare metals. This project studies the ability of a less expensive metal, cobalt, to activate hydrogen. As the details of how hydrogen adds to various compounds is difficult to determine, an unusual form of hydrogen known as parahydrogen will be used in this study to increase the sensitivity of measurements up to 200,000 times. In addition, the project aims to improve diversity, equity, and inclusion in the next generation of scientists. Prof. Fout and her students will participate in the 3M Summer Scholars Program, which aims to provide research experiences to undergraduate students from underrepresented groups, the Next Generation Illinois Scientist, which engages elementary students in rural schools, and the Bonding Camp for Girls, which targets 6-8th grade girls.This project synthesizes cobalt complexes that may serve as parahydrogen-induced polarization (PHIP) catalysts. This requires diamagnetic complexes that remain S=0 throughout the catalytic cycle for both direct and indirect hyperpolarization. To achieve this and to access a Co(I)/Co(III) catalytic cycle, complexes of ligands containing electron-rich moieties and carbenes are prepared. Their activity to catalyze PHIP is evaluated across a range of substrates including olefins, alkynes, and arenes, which feature long-relaxing nuclei in their functional groups. Some of the substrates are key reactants in polymerization catalysis. In these cases, the PHIP effect is used to detect and study of mechanistic intermediates that have not previously been observed.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.