Collaborative Research: Continuous-Flow Hyperpolarization of Liquids Utilizing Parahydrogen and Heterogeneous Catalysis

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With support from the Chemical Measurement and Imaging (CMI) Program in the Division of Chemistry (CHE), and partial co-funding from two other CHE programs, Chemical Structures, Dynamics, and Mechanisms - A (CSDM-A) , and Chemical Catalysis (CAT) and also from the Molecular Biophysics Cluster in the Molecular and Cellular Biosciences (MCB) Division, Professors Clifford R. Bowers at the University of Florida and Wenyu Huang at Iowa State University seek to develop new instrumentation and protocols for enhancing the sensitivity of nuclear magnetic resonance (NMR) spectroscopy, an important method for characterizing the composition and structure of chemical structures and the foundation of magnetic resonance imaging – a major tool for medical diagnostics. The team is developing continuous-flow methods and advanced intermetallic nanoparticle catalysts in efforts to improve the sensitivity of NMR spectroscopy by more than a factor of 10,000. The research will provide research experiences for high school and undergraduate students coordinated through the Center for Pre-collegiate Education and Training (CPET) at the University of Florida and several NSF Research Experiences for Undergraduates (REU) programs. In Ames, Iowa, outreach activities additionally include science shows and involvement of undergraduates and high school students in research activities and demonstrations incorporating project concepts.Nuclear Magnetic Resonance (NMR) relies on population differences among nuclear spin energy levels (i.e. spin polarization) in a molecule. In conventional NMR, spin polarization is induced by placing the sample in a high static magnetic field. However, even at the highest available magnetic fields, thermal equilibrium spin polarizations near ambient temperature are no greater than about 0.01%, and hence the NMR transition intensities are inherently weak. Parahydrogen-based hyperpolarization can provide a robust and cost-effective method that is scalable and compatible with rapid and continuous production of molecules in fluids with polarizations approaching 100%. For production of hyperpolarized liquids from parahydrogen, heterogeneous catalysis offers key benefits: the solid catalysts can provide consistent activity (under appropriate conditions) and the catalyst material can be easily separated from dissolved hyperpolarization products. Advancement of solution-state hyperpolarization from parahydrogen and heterogeneous catalysis requires a clear understanding of the catalytic mechanism and parahydrogen spin dynamics after dissociation of the molecule. The development of parahydrogen-enhanced polarization by continuous-flow heterogeneous catalysis will facilitate fundamental studies of the underlying mechanisms and spin dynamics of hyperpolarization from hydrogenation reactions as well as non-hydrogenative processes such as surface-mediated hyperpolarization from parahydrogen.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.