A controlled System for Parahydrogen Hyperpolarization experiments

These data corresponds to the paper: 

A controlled System for Parahydrogen Hyperpolarization experiments

Journal: Molecules

Year: 2025

Lorenzo Franco 1, Federico Floreani 1, Salvatore Mamone 2, Ahmed Mohammed Faramawy 1, Marco Ruzzi 1, Cristina Tubaro 1 and Gabriele Stevanato 1,*

1    Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1, 35131, Padova, Italy;

2    Dept. MESVA (Life, Health & Environmental Sciences), Università dell’Aquila, Via Vetoio SNC, Localita' Coppito, 67100, L'Aquila, Italy

   Correspondence: [e-mail]

ABSTRACT:

Parahydrogen-induced hyperpolarization (PHIP), introduced nearly four decades ago, provides an elegant solution to one of the fundamental limitations of nuclear magnetic resonance (NMR) — its notoriously low sensitivity. By converting the spin order of parahydrogen into nuclear spin polarization, NMR signals can be boosted by several orders of magnitude. Here we present a portable, compact and cost-effective setup that brings PHIP and Signal Amplification By Reversible Exchange (SABRE) experiments within easy reach, operating seamlessly across ultra-low-field (0–10 μT) and high-field (>1 T) conditions at 50% parahydrogen enrichment. The system provides precise control over bubbling pressure, temperature, and gas flow, enabling systematic studies of how these parameters shape hyperpolarization performance. Using the benchmark Chloro(1,5-cyclooctadiene)[1,3-bis(2,4,6-trimethylphenyl)imidazole-2-ylidene]iridium(I) (Ir-Imes) catalyst, we explore the catalyst activation time and response to parahydrogen flow and pressure. Polarization transfer experiments from hydrides to [1-13C]pyruvate leading to the estimation of heteronuclear J-couplings are also presented. We further demonstrate the use of Chloro(1,5-cyclooctadiene)[1,3-bis(2,6-diisopropylphenyl)imidazolidin-2-ylidene]iridium(I) (Ir-SIPr), a recently introduced catalyst that can also be used for pyruvate hyperpolarization. The proposed design is robust, reproducible, and easy to implement in any laboratory, widening the route to explore and expand the capabilities of parahydrogen-based hyperpolarization.

FUNDING

This research has been funded/co-funded by the European Union (ERC StG, HYPMET, 101117082). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them.

ACKNOWLEDGEMENTS

GS acknowledges the internal mechanical and electrical workshop, specifically Lorenzo Dainese, Roberto Inilli and Claudio Comaron for their assistance in building the parahydrogen generator and the distribution system. GS also acknowledges Prof. Fabrizio Mancin and Prof. Federico Rastrelli from Università degli Studi di Padova (IT) for the use of the XPulse benchtop NMR spectrometer. Part of the data have been adapted from our recent publication (DOI: https://doi.org/10.1039/D5CP01773D) with permission from the RSC.