biostudies-literatureUnknownGriffiths EFRoyal Society of ChemistryCaffyn Family Charitable FundManchester Metropolitan UniversityBrønsted acids, such as phosphoric acids derived from chiral 1,1'-bi-2-naphthol (BINOL), are important catalysts in the formation of carbon-carbon and carbon-heteroatom bonds, for example. The catalytic activity of these Brønsted acids is strongly linked to their acidity, and as such, the evaluation of compounds to determine pK_a values provides insight into their catalytic activity. Herein, a ¹⁹F{¹H} NMR methodology is detailed to determine the pK_a of a fluorinated binaphthyl-derived phosphinic acid, rac-1, in acetonitrile and in the presence of a fluorinated sulfonamide reference compound (2-4). The approach was tested initially using 2 and 3, with the ΔpK_a (0.08) in strong agreement with previously reported values (6.6 for 2 and 6.68Magnetic resonance in chemistry : MRChttps://www.ebi.ac.uk/biostudies/studies/S-EPMC11608935biostudies-literatureDetermination of the pK<sub>a</sub> Value of a Bronsted Acid by <sup>19</sup>F NMR Spectroscopy.PMC11608935E21‐4481742304E21-4481742304Macia BCaffyn AJMLangley SKMewis REDixon JAGriffiths EFCaprio VfalseDetermination of the pK<sub>a</sub> Value of a Bronsted Acid by <sup>19</sup>F NMR Spectroscopy.Brønsted acids, such as phosphoric acids derived from chiral 1,1'-bi-2-naphthol (BINOL), are important catalysts in the formation of carbon-carbon and carbon-heteroatom bonds, for example. The catalytic activity of these Brønsted acids is strongly linked to their acidity, and as such, the evaluation of compounds to determine pK_a values provides insight into their catalytic activity. Herein, a ¹⁹F{¹H} NMR methodology is detailed to determine the pK_a of a fluorinated binaphthyl-derived phosphinic acid, rac-1, in acetonitrile and in the presence of a fluorinated sulfonamide reference compound (2-4). The approach was tested initially using 2 and 3, with the ΔpK_a (0.08) in strong agreement with previously reported values (6.6 for 2 and 6.682024-01-01T00:00:00Z2024 Oct2025-04-05T14:59:53.611Z2025-04-05T14:59:53.611ZS-EPMC116089353941546110.1002/mrc.5485