Solution-State High Field DNP on Large Volume Samples: Sensitivity-Enchanced NMR for the Organic Chemist

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With support from the Chemical Measurement and Imaging (CMI) Program in the Division of Chemistry, Dr. Sungsool Wi and his team at the National High Magnetic Field Laboratory (NHMFL) at Florida State University are devising new methods to advance the capabilities of nuclear magnetic resonance (NMR) spectroscopy – a leading means of characterizing the structure and dynamics of organic molecules. Complementary innovative paths are being pursued to substantially improve the NMR sensitivity and to provide correspondingly lower limits of detection for a wider range of target molecules. If successful, these methods would provide new opportunities for characterizing molecules in many different areas of scientific and industrial applications, including studies of pharmaceuticals, metabolites in human and animal studies, natural products, food and polymer additives, and small molecules in natural crude oil. Tools developed will be made available to local and remote users of NHMFL. This project provides valuable training opportunities to participating student and postdoctoral trainees, including summer internships offering hands-on experience for undergraduate students. The Wi team has identified two independent, complementary approaches to enhancing the NMR signals of arbitrary molecules. One relies on the use of low-viscosity supercritical solvents to enable electron-to-nucleus Overhauser-based dynamic nuclear polarization (ODNP). The other relies on hitherto unknown relaxation processes arising in biradicals to enable transfers from two J-coupled electrons to one nucleus over a wide variety of fields and correlation times. The Wi group will leverage these technological and conceptual breakthroughs to enable sensitivity-enhanced DNP spectroscopy at high fields on ~100 μL solution-state samples containing dilute organic molecules, with the aim of potentially creating a new paradigm in NMR.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.