Determination of the pK_a Value of a Bronsted Acid by ¹⁹F NMR Spectroscopy.

ABSTRACT: 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 6.68

SUBMITTER: Griffiths EF 

PROVIDER: S-EPMC11608935 | biostudies-literature | 2024 Oct

REPOSITORIES: biostudies-literature