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Harnessing asymmetric N-heterocyclic carbene ligands to optimise SABRE hyperpolarisation.

ABSTRACT: The catalytic signal amplification by reversible exchange process has become widely used for the hyperpolarisation of small molecules to improve their magnetic resonance detectability. It harnesses the latent polarisation of parahydrogen, and involves the formation of a labile metal complex that often contains an N-heterocyclic carbene (NHC) ligand (e.g. [Ir(H)2(NHC)(pyridine)3]Cl), which act as a polarisation transfer catalyst. Unfortunately, if the target molecule is too bulky, binding to the catalyst is poor and the hyperpolarisation yield is therefore low. We illustrate here the behaviour of a series of asymmetric NHC containing catalysts towards 3,4- and 3,5-lutidine in order to show how catalyst design can be used to dramatically improve the outcome of this catalytic process for sterically encumbered ligands.

SUBMITTER: Wong CM

PROVIDER: S-EPMC6171487 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature

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Harnessing asymmetric N-heterocyclic carbene ligands to optimise SABRE hyperpolarisation.

Wong Chin Min CM Fekete Marianna M Nelson-Forde Rhianna R Gatus Mark R D MRD Rayner Peter J PJ Whitwood Adrian C AC Duckett Simon B SB Messerle Barbara A BA

Catalysis science & technology 20180903 19

The catalytic signal amplification by reversible exchange process has become widely used for the hyperpolarisation of small molecules to improve their magnetic resonance detectability. It harnesses the latent polarisation of parahydrogen, and involves the formation of a labile metal complex that often contains an N-heterocyclic carbene (NHC) ligand (e.g. [Ir(H)2(NHC)(pyridine)3]Cl), which act as a polarisation transfer catalyst. Unfortunately, if the target mo ...[more]

PMID: 30319759

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