Reaction monitoring using SABRE-hyperpolarized benchtop (1 T) NMR spectroscopy
Semenova, Olga and Richardson, Peter Michael and Parrott, Andrew J and Nordon, Alison and Halse, Meghan E and Duckett, Simon B (2019) Reaction monitoring using SABRE-hyperpolarized benchtop (1 T) NMR spectroscopy. Analytical Chemistry, 91 (10). pp. 6695-6701. ISSN 0003-2700 (https://doi.org/10.1021/acs.analchem.9b00729)
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Abstract
The conversion of [IrCl(COD)(IMes)] (COD = cis,cis-1,5-cyclooctadiene, IMes = 1,3-bis(2,4,6-trimethyl-phenyl)imidazole-2-ylidene) in the presence of an excess of p-H2 and a substrate (4-aminopyridine (4-AP) or 4-methylpyridine (4-MP)) into [Ir(H)2(IMes)(substrate)3]Cl is monitored by 1H NMR spectroscopy using a benchtop (1 T) spectrometer in conjunction with the parahydrogen (p-H2) based hyperpolarization technique signal amplification by reversible exchange (SABRE). A series of single-shot 1H NMR measurements are used to monitor the chemical changes that take place in solution through the lifetime of the hyperpolarized response. Non-hyperpolarized high-field 1H NMR control measurements were also undertaken to confirm that the observed time dependent changes relate directly to the underlying chemical evolution. The formation of [Ir(H)2(IMes)(substrate)3]Cl is further linked to the hydrogen isotope exchange reaction (HIE) which leads to the incorporation of deuterium into the ortho positions of 4-AP, where the source of deuterium is the solvent, methanol-d4. Comparable reaction monitoring results are achieved at both high-field (9.4 T) and low-field (1 T). It is notable, that the low sensitivity of the benchtop (1 T) NMR enables the use of protio solvents, which is harnessed here to separate the effects of catalyst formation and substrate deuteration. Collectively, these methods illustrate how low-cost low-field NMR measurements provide unique insight into a complex catalytic process through a combination of hyperpolarization and relaxation data.
ORCID iDs
Semenova, Olga, Richardson, Peter Michael, Parrott, Andrew J ORCID: https://orcid.org/0000-0002-4598-2736, Nordon, Alison ORCID: https://orcid.org/0000-0001-6553-8993, Halse, Meghan E and Duckett, Simon B;-
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Item type: Article ID code: 67601 Dates: DateEvent21 May 2019Published15 April 2019Published Online8 February 2019AcceptedSubjects: Science > Chemistry Department: Faculty of Science > Pure and Applied Chemistry
Technology and Innovation Centre > Continuous Manufacturing and Crystallisation (CMAC)Depositing user: Pure Administrator Date deposited: 17 Apr 2019 11:25 Last modified: 10 Sep 2024 05:33 URI: https://strathprints.strath.ac.uk/id/eprint/67601