Collaborative Research: Exploiting Spin Networks and Efficient Catalyst/Substrate Separations for NMR "SABRE" Enhancement of Complex Systems

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With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professors Boyd Goodson at Southern Illinois University (SIU) and Eduard Chekmenev at Wayne State University (WSU) are working to improve the sensitivity of nuclear magnetic resonance (NMR), an important method of chemical analysis which underlies the well-known clinical imaging modality, magnetic resonance imaging (MRI). The Goodson/Chekmenev team is developing new, inexpensive, and easy-to-make means of enhancing nuclear magnetization - a sensitivity-limiting factor in many NMR and MRI applications, including diagnostic tests for a host of diseases. Anticipated cost savings can also make these methods more available for other lab settings, particularly those that have more limited research infrastructure and/or that feature undergraduate research. Several students are involved, gaining exposure to highly interdisciplinary training. The team is also engaged in efforts to recruit undergraduate students and match them with a variety of mentored research opportunities on both campuses, with a goal of increasing the numbers and diversity of undergraduate students seeking STEM careers. The NMR/MRI approaches being used are based on Signal Amplification by Reversible Exchange, or SABRE. In SABRE, an organometallic catalyst is used to co-locate parahydrogen and a target molecule (substrate) within a transient complex; with properly matched external magnetic fields, nuclear spin order can transfer spontaneously and efficiently from parahydrogen to the substrate, giving rise to NMR and MRI signals that are increased by several orders of magnitude. Work by the Goodson/Chekmenev team seeks to: (1) improve the understanding and utility of long-range SABRE polarization transfer via spin-relay networks in model systems, for both homonuclear and heteronuclear cases; (2) develop and characterize new heterogeneous catalysts for SABRE ("HET-SABRE"), as well as approaches for catalyst recovery; and (3) broaden the range of substances amenable to SABRE through improved understanding of the fundamental quantum mechanics of complex spin behavior in model extended networks.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.