The inherently low sensitivity of nuclear magnetic resonance (NMR) spectroscopy is the major limiting factor for its application to elucidate structure and dynamics in solids. In the solid state, nuclear spin hyperpolarization methods based on microwave-induced dynamic nuclear polarization (DNP) provide a versatile platform to enhance the bulk NMR signal of many different sample formulations, leading to significant sensitivity improvements. Here we show that H NMR hyperpolarization can also be generated in solids at high magnetic fields by optical irradiation of the sample. We achieved this by exploiting a donor-chromophore-acceptor molecule with an excited state electron-electron interaction similar to the nuclear Larmor frequency, enabling solid-state H photochemically induced DNP (photo-CIDNP) at high magnetic fields. Through hyperpolarization relay, we obtained bulk NMR signal enhancements ε by factors of ∼100 at both 9.4 and 21.1 T for the H signal of -terphenyl in magic angle spinning (MAS) NMR experiments at 100 K. These findings open a pathway toward a general light-induced hyperpolarization approach for dye-sensitized high-field NMR in solids.
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http://dx.doi.org/10.1021/jacs.4c06151 | DOI Listing |
Anal Chem
January 2025
Institute for Bioengineering of Catalonia (IBEC), Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain.
Nuclear magnetic resonance (NMR) spectroscopy is a valuable diagnostic tool limited by low sensitivity due to low nuclear spin polarization. Hyperpolarization techniques, such as dissolution dynamic nuclear polarization, significantly enhance sensitivity, enabling real-time tracking of cellular metabolism. However, traditional high-field NMR systems and bioreactor platforms pose challenges, including the need for specialized equipment and fixed sample volumes.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
International Tomography Center, SB RAS, 3A Institutskaya St., Novosibirsk 630090, Russia.
Nuclear magnetic resonance is extremely attractive for operando studies of chemical reactors. However, the heterogeneous catalyst particles placed inside an NMR probe greatly affect the uniformity of the magnetic field. This problem is especially acute when studying heterogeneous hydrogenation processes using parahydrogen.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr, Tallahassee, Florida 32310, United States.
The contribution of protons in or near biradical polarizing agents in Dynamic Nuclear Polarization (DNP) has recently been under scrutiny. Results from selective deuteration and simulations have previously suggested that the role of protons in the biradical molecule depends on the strength of the electron-electron coupling. Here we use the cross effect DNP mechanism to identify and acquire H solid-state NMR spectra of the protons that contribute to propagation of the hyperpolarization, via an experimental approach dubbed Nuclear-Nuclear Double Resonance (NUDOR).
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Department of Structural Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, USA.
Bacterial biofilms are major contributors to persistent infections and antimicrobial resistance, posing significant challenges to treatment. However, obtaining high-resolution structural information on native bacterial biofilms has remained elusive due to the methodological limitations associated with analyzing complex biological samples. Solid-state NMR (ssNMR) has shown promise in this regard, but its conventional application is hindered by sensitivity constraints for unlabeled samples.
View Article and Find Full Text PDFNatl Sci Rev
January 2025
State Key Laboratory of Physical Chemistry of Solid Surfaces, School of Electronic Science and Engineering, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
Heterogeneous catalysts for parahydrogen-induced polarization (HET-PHIP) would be useful for producing highly sensitive contrasting agents for magnetic resonance imaging (MRI) in the liquid phase, as they can be removed by simple filtration. Although homogeneous hydrogenation catalysts are highly efficient for PHIP, their sensitivity decreases when anchored on porous supports due to slow substrate diffusion to the active sites and rapid depolarization within the channels. To address this challenge, we explored 2D metal-organic layers (MOLs) as supports for active Rh complexes with diverse phosphine ligands and tunable hydrogenation activities, taking advantage of the accessible active sites and chemical adaptability of the MOLs.
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