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Light-Induced 1H NMR Hyperpolarization in Solids at 9.4 and 21.1 T.
Federico De Biasi1, Ganesan Karthikeyan2, Máté Visegrádi1
1Institut des Sciences et Ingenierie Chimiques, École Polytechnique Fedérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Journal of the American Chemical Society
|July 15, 2024
Summary
Researchers developed a new method to boost nuclear magnetic resonance (NMR) sensitivity in solids using light. This photochemical approach enhances signals by 100-fold, enabling detailed solid-state NMR studies.
Area of Science:
- Solid-state Nuclear Magnetic Resonance (NMR) Spectroscopy
- Photochemistry
- Hyperpolarization Techniques
Background:
- Low sensitivity is a key limitation for solid-state NMR applications.
- Dynamic Nuclear Polarization (DNP) using microwaves significantly enhances NMR signal sensitivity.
- Existing DNP methods are effective but can be limited in scope or application.
Purpose of the Study:
- To develop a novel method for generating 1H NMR hyperpolarization in solids using optical irradiation.
- To overcome the sensitivity limitations of conventional solid-state NMR.
- To enable high-field NMR studies in solids through light-induced signal enhancement.
Main Methods:
- Utilized a donor-chromophore-acceptor molecule with specific excited state electron-electron interactions.
- Implemented solid-state 1H photochemically induced dynamic nuclear polarization (photo-CIDNP) at high magnetic fields (9.4 and 21.1 T).
- Employed hyperpolarization relay and magic angle spinning (MAS) NMR at 100 K.
Main Results:
- Achieved bulk 1H NMR signal enhancements (εH) of approximately 100-fold.
- Demonstrated successful hyperpolarization at both 9.4 T and 21.1 T.
- Obtained enhanced 1H NMR signals for o-terphenyl in solid samples.
Conclusions:
- Established a viable light-induced hyperpolarization method for solid-state NMR.
- Photo-CIDNP offers a promising alternative to microwave-based DNP for sensitivity enhancement.
- This approach paves the way for general dye-sensitized high-field NMR in solids.
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