Abstract: Nuclear spin hyperpolarization boosts NMR sensitivity but typically requires complex infrastructure. Signal Amplification by Reversible Exchange (SABRE), a parahydrogenbased hyperpolarization technique, can be conducted using a remarkably low-cost polarizer (<$100) comprising only magnetic coils and a standard PC sound card, avoiding magnetic shielding. However, under these conditions SABRE requires direct spin-coupling between parahydrogen and the target nucleus, limiting its application to distant heteronuclear spins such as 77Se in biologically relevant selenium-nitrogen heterocycles (e.g. antioxidant, antiviral, and anticancer agents). Here, we overcome the distance restrictions by developing the 15N-mediated polarization transfer driven by oscillating magnetic fields of the audio frequency. As a proof-of-concept, we achieve a 11600-fold enhancement of the 77Se NMR signal (>6% net polarization) at 9.4 T in a shielding-free setup using a selenadiazole derivative. These results suggest that selenadiazole-based compounds are particularly well suited for this strategy and provide a basis for extending it to other selenium-containing molecules.

Cite: Markelov D.A. , Kiryutin A.S. , Borisov A.V. , Kosenko I.D. , Godovikov I.A. , Yurkovskaya A.V.
77Se Hyperpolarization Enabled by Reversible Parahydrogen Exchange and Audio-Frequency Magnetic Fields at 0.1 mT
Parahydrogen Enhanced Resonance Meeting 03-05 Nov 2025