Solid-Effect Dynamic Nuclear Polarization in Viscous Liquids at 9.4 T Using Narrow-Line Polarizing Agents

Andrei A Kuzhelev; Vasyl Denysenkov; Iram M Ahmad; Olga Yu Rogozhnikova; Dmitry V Trukhin; Elena G Bagryanskaya; Victor M Tormyshev; Snorri Th Sigurdsson; Thomas F Prisner

doi:10.1021/jacs.3c01358

Solid-Effect Dynamic Nuclear Polarization in Viscous Liquids at 9.4 T Using Narrow-Line Polarizing Agents

J Am Chem Soc. 2023 May 10;145(18):10268-10274. doi: 10.1021/jacs.3c01358. Epub 2023 Apr 27.

Authors

Andrei A Kuzhelev¹, Vasyl Denysenkov¹, Iram M Ahmad², Olga Yu Rogozhnikova³, Dmitry V Trukhin³, Elena G Bagryanskaya³, Victor M Tormyshev³, Snorri Th Sigurdsson², Thomas F Prisner¹

Affiliations

¹ Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max von Laue Straße 7, 60438 Frankfurt am Main, Germany.
² Department of Chemistry, Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavik, Iceland.
³ N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Acad. Lavrentiev Avenue 9, 630090 Novosibirsk, Russia.

PMID: 37104685
DOI: 10.1021/jacs.3c01358

Abstract

Dynamic nuclear polarization (DNP) is a hyperpolarization method that is widely used for increasing the sensitivity of nuclear magnetic resonance (NMR) experiments. DNP is efficient in solid-state and liquid-state NMR, but its implementation in the intermediate state, namely, viscous media, is still less explored. Here, we show that a ¹H DNP enhancement of over 50 can be obtained in viscous liquids at a magnetic field of 9.4 T and a temperature of 315 K. This was accomplished by using narrow-line polarizing agents in glycerol, both the water-soluble α,γ-bisdiphenylen-β-phenylallyl (BDPA) and triarylmethyl radicals, and a microwave/RF double-resonance probehead. We observed DNP enhancements with a field profile indicative of the solid effect and investigated the influence of microwave power, temperature, and concentration on the ¹H NMR results. To demonstrate potential applications of this new DNP approach for chemistry and biology, we show hyperpolarized ¹H NMR spectra of tripeptides, triglycine, and glypromate, in glycerol-d₈.