Hyperpolarisation of weakly binding N-heterocycles using Signal Amplification by Reversible Exchange

Peter John Rayner, Joseph Gillions, Valentin Hannibal, Richard Owain John, Simon B. Duckett

Research output: Contribution to journalArticlepeer-review


Signal Amplification by Reversible Exchange (SABRE) is a catalytic method for improving the detection of molecules by magnetic resonance spectroscopy. It achieves this by simultaneously binding the target substrate (sub) and para-hydrogen to a metal centre. To date, sterically large substrates are relatively inacessable to SABRE due to their weak binding leading to catalyst destabilisation. We overcome this problem here through a simple co-ligand strategy that allows the hyperpolarisation of a range of weakly binding and sterically encumbered N-heterocycles. The resulting 1H NMR signal size is increased by up to 1400 times relative to their more usual Boltzmann controlled levels at 400 MHz. Hence, a significant reduction in scan time is achieved. The SABRE catalyst in these systems takes the form [IrX(H)2(NHC)(sulfoxide)(sub)] where X = Cl, Br or I. These complexes are shown to undergo very rapid ligand exchange and lower temperatures dramatically improves the efficiency of these SABRE catalysts.
Original languageEnglish
Pages (from-to)5910-5917
JournalChemical Science
Issue number16
Early online date23 Mar 2021
Publication statusPublished - 28 Apr 2021

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© 2021 The Author(s). Published by the Royal Society of Chemistry.

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