585. Hyperpolarized Solution-State NMR Spectroscopy with Optically Polarized Crystals
Tim R. Eichhorn, Anna J. Parker, Felix Josten, Christoph Müller, Jochen Scheuer, Jakob M. Steiner, Martin Gierse, Jonas Handwerker, Michael Keim, Sebastian Lucas, Mohammad Usman Qureshi, Alastair Marshall, Alon Salhov, Yifan Quan, Jan Binder, Kay D. Jahnke, Philipp Neumann, Stephan Knecht, John W. Blanchard, Martin B. Plenio, Fedor Jelezko, Lyndon Emsley, Christophoros C. Vassiliou, Patrick Hautle, Ilai Schwartz, JAmChemSoc, (2022), DOI: 10.1021/jacs.1c09119
Nuclear spin hyperpolarization provides a promising route to overcome the challenges imposed by the limited sensitivity of nuclear magnetic resonance. Here we demonstrate that dissolution of spin-polarized pentacene-doped naphthalene crystals enables transfer of polarization to target molecules via intermolecular cross-relaxation at room temperature and moderate magnetic fields (1.45 T). This makes it possible to exploit the high spin polarization of optically polarized crystals, while mitigating the challenges of its transfer to external nuclei. With this method, we inject the highly polarized mixture into a benchtop NMR spectrometer and observe the polarization dynamics for target 1H nuclei. Although the spectra are radiation damped due to the high naphthalene magnetization, we describe a procedure to process the data to obtain more conventional NMR spectra and extract the target nuclei polarization. With the entire process occurring on a time scale of 1 min, we observe NMR signals enhanced by factors between −200 and −1730 at 1.45 T for a range of small molecules.