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Towards Large-Scale Steady-State Enhanced Nuclear Magnetization with In Situ Detection

preprint
submitted on 13.01.2021, 11:17 and posted on 18.01.2021, 04:59 by John Blanchard, Barbara Ripka, Benjamin A. Suslick, Dario Gelevski, Teng Wu, Kerstin Münnemann, Danila Barskiy, Dmitry Budker
Signal Amplification By Reversible Exchange (SABRE) boosts NMR signals of various nuclei enabling new applications spanning from magnetic resonance imaging to analytical chemistry and fundamental physics. SABRE is especially well positioned for continuous generation of enhanced magnetization on a large scale, however, several challenges need to be addressed for accomplishing this goal. Specifically, SABRE requires (i) a specialized catalyst capable of reversible H2 activation and (ii) physical transfer of the sample from the point of magnetization generation to the point of detection (e.g., a high-field or a benchtop NMR spectrometer). Moreover, (iii) continuous parahydrogen bubbling accelerates solvent (e.g., methanol) evaporation, thereby limiting the experimental window to tens of minutes per sample.
In this work, we demonstrate a strategy to rapidly generate the best-to-date precatalyst (a compound that is chemically modified in the course of the reaction to yield the catalyst) for SABRE, [Ir(IMes)(COD)Cl] (IMes = 1,3-bis-(2,4,6-trimethylphenyl)-imidazol-2-ylidene, COD = cyclooctadiene) via a highly accessible synthesis. Second, we measure hyperpolarized samples using a home-built zero-field NMR spectrometer and study the field dependence of hyperpolarization directly in the detection apparatus, eliminating the need to physically move the sample during the experiment. Finally, we prolong the measurement time and reduce evaporation by presaturating parahydrogen with the solvent vapor before bubbling into the sample. These advancements extend opportunities for exploring SABRE hyperpolarization by researchers from various fields and pave the way to producing large quantities of hyperpolarized material for long-lasting detection of SABRE-derived nuclear magnetization.

Funding

Alexander von Humboldt Foundation (Sofja Kovalevskaja Award)

Heising-Simons Foundation

European Research Council under the European Union’s Horizon 2020 Research and Innovative Programme under Grant agreement No.695405

History

Email Address of Submitting Author

dbarskiy@uni-mainz.de

Institution

Helmholtz-Institute Mainz

Country

Germany

ORCID For Submitting Author

0000-0002-2819-7584

Declaration of Conflict of Interest

No conflict of interest

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