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Updated: Jun 8, 2025

Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method
Published on: July 19, 2019
Identifying routes for transferring spin polarization from parahydrogen to protic solvents
Ewoud Vaneeckhaute1,2,3, Jean-Max Tyburn4, James G Kempf5
1NMRCoRe, NMR/X-Ray Platform for Convergence Research, KU Leuven, Celestijnenlaan 200F, box 2461, B-3001 Leuven, Belgium. ewoud.vaneeckhaute@kuleuven.be.
Abstract:
Repeatable hyperpolarization of high concentrations of mobile protons (>6 M) using parahydrogen in protic methanol/water mixtures is reported here. Different ammonium buffers with increasing mobile proton concentrations were added to an IrCl(COD)(IMes) catalyst in the presence of pyridine. We reach a maximum molar polarization of 1.79 mM at 6 mT. Field-cycling experiments in an 18.8 T detection field distinguished two solvent polarization transfer pathways: chemical exchange with labile protons from ammonia and cross-relaxation with pyridine aromatic protons.
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