The theory and practice of hyperpolarization in magnetic resonance using parahydrogen

Green, Richard A.; Adams, Ralph W.; Duckett, Simon B.; Mewis, Ryan E.; Williamson, D.S.; Green, Gary

doi:10.1016/j.pnmrs.2012.03.001

Cited by 329 publications

(295 citation statements)

References 199 publications

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“…Hyperpolarisation methods are being used widely to improve the sensitivity of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) to substrate detection 1, 2. Signal amplification by reversible exchange (SABRE) is one such method where the nuclear spin order from para hydrogen ( p ‐H 2 ) is used to sensitise substrate detection 3, 4, 5.…”

Section: Introductionmentioning

confidence: 99%

“…Another is the use of high‐sensitivity methods in analytical chemistry. [ 10 , 13 ] Other routes to hyperpolarisation include dynamic nuclear polarisation,2 parahydrogen‐induced polarisation[ 6 , 14 ] with substrate functionalisation and spin‐exchange optical pumping. [ 10 , 15 ]…”

Section: Introductionmentioning

confidence: 99%

“…Here, we show that, for type 2 complexes, the acetonitrile ligand is more labile than indazole and imidazole. The level of signal enhancement resulting from SABRE relates to the ligand exchange rate constants because polarisation transfer proceeds via the small J‐coupling that exists between the hydride ligand and polarisation acceptor 2. Understanding these effects is critical to optimisation of SABRE 2.…”

Section: Introductionmentioning

confidence: 99%

“…The level of signal enhancement resulting from SABRE relates to the ligand exchange rate constants because polarisation transfer proceeds via the small J‐coupling that exists between the hydride ligand and polarisation acceptor 2. Understanding these effects is critical to optimisation of SABRE 2. It has also been suggested that because transfer is slow, relaxation by the SABRE catalyst can limit performance,27 and a simple and readily understandable model to assess this has been reported by Koptyug [11d] .…”

Section: Introductionmentioning

confidence: 99%

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Harnessing polarisation transfer to indazole and imidazole through signal amplification by reversible exchange to improve their NMR detectability

Fekete

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et al. 2017

Magnetic Reson in Chemistry

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The signal amplification by reversible exchange (SABRE) approach has been used to hyperpolarise the substrates indazole and imidazole in the presence of the co‐ligand acetonitrile through the action of the precataysts [IrCl(COD)(IMes)] and [IrCl(COD)(SIMes)]. 2H‐labelled forms of these catalysts were also examined. Our comparison of the two precatalysts [IrCl(COD)(IMes)] and [IrCl(COD)(SIMes)], coupled with 2H labelling of the N‐heterocyclic carbene and associated relaxation and polarisation field variation studies, demonstrates the critical and collective role these parameters play in controlling the efficiency of signal amplification by reversible exchange. Ultimately, with imidazole, a 700‐fold1H signal gain per proton is produced at 400 MHz, whilst for indazole, a 90‐fold increase per proton is achieved. The co‐ligand acetonitrile proved to optimally exhibit a 190‐fold signal gain per proton in these measurements, with the associated studies revealing the importance the substrate plays in controlling this value. Copyright © 2017 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Harnessing polarisation transfer to indazole and imidazole through signal amplification by reversible exchange to improve their NMR detectability

Fekete

Rayner

Green

et al. 2017

Magnetic Reson in Chemistry

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“…Any increase by technical means will significantly extend the possibility range of NMR application.”1 This quotation from Richard Ernst's Nobel prize lecture sets the stage for numerous studies and approaches to improve the signal‐to‐noise‐ratio (S/N) in NMR. In recent years, many different methods, including PHIP,2 SABRE,2 hyperpolarized noble gases,3 MAS DNP,4 nitrogen vacancies in diamonds,5 dissolution DNP,6 and DNP in the solid‐state,7 have been developed, and a summary of these can be found in a recent review article in Angewandte Chemie 8…”

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confidence: 99%

Unprecedented Carbon Signal Enhancement in Liquid‐State NMR Spectroscopy

Pintér

Schwalbe

2017

Angew Chem Int Ed

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Miniature and Tabletop Nuclear Magnetic Resonance Spectrometers

Blümich

2016

Encyclopedia of Analytical Chemistry

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The most striking component of nuclear magnetic resonance (NMR) spectrometers for chemical analysis used to be a large super‐conducting, confining NMR spectrometers to dedicated laboratories away from the chemical work bench. This situation has changed in 2010 with the invention of small permanent magnets capable of providing magnetic fields sufficiently homogeneous and stable to resolve the chemical shift. Up to then NMR with compact magnets was limited to materials testing by relaxation and diffusion measurements without chemical resolution. While sensitivity and spectral dispersion of high‐resolution tabletop NMR spectrometers are lower than those of hitherto conventional high‐field NMR spectrometers due to lower field strength, they can be operated with the whole methodology known from high‐field NMR but inside the chemical laboratory and under the fume hood. This shortens the time for chemical analysis in reaction control applications from hours to minutes and opens up new opportunities for reaction monitoring and analysis of hazardous compounds. The lower cost makes NMR available to a wider user community and drives the progress in simplification and automation of the measurement process. In the following, compact NMR machines and their uses for materials testing and chemical analysis are reviewed.

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The theory and practice of hyperpolarization in magnetic resonance using parahydrogen

Cited by 329 publications

References 199 publications

Harnessing polarisation transfer to indazole and imidazole through signal amplification by reversible exchange to improve their NMR detectability

Harnessing polarisation transfer to indazole and imidazole through signal amplification by reversible exchange to improve their NMR detectability

Unprecedented Carbon Signal Enhancement in Liquid‐State NMR Spectroscopy

Miniature and Tabletop Nuclear Magnetic Resonance Spectrometers

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