High H2 Solubility of Perfluorocarbon Solvents and Their Use in 2 Reversible Polarization Transfer from para-Hydrogen

This research uses perfluorocarbons (PFCs) as effective alternatives to traditional toxic solvents in reversible para-hydrogen-induced polarization (PHIP) for NMR signal en-hancement. Hydrogen solubility in PFCs is shown here to be an order of magnitude higher than in typical organic sol-vents by determination of Henry’s constants. We demon-strate how this high H2 solubility enables the PFCs to deliver substantial polarization transfer from parahydrogen, achiev-ing up to 2,400-fold signal gains for 1H NMR detection and 67,000-fold (22% polarization) for 15N NMR detection at 9.4 T in substrates like pyridine and nicotine. Notably, methylperfluorobutylether outperforms catalytic efficiency in methanol-d4 and dichloromethane-d2 for pyridine at low catalyst loadings. This makes PFCs particularly advanta-geous for applications demanding high NMR sensitivity. With high polarization efficiency and reduced toxicity, PFCs hold strong potential for expanding NMR applications across biomedical and analytical fields.