Hyperpolarization Catalysts for in situ Mechanistic Studies

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.