The species-specific acid-base and multinuclear magnetic resonance properties of selenocysteamine, selenocysteine, and their homodiselenides

Abstract Selenol-compounds were studied by 1H, 13C, and 77Se NMR spectroscopy as a function of pH, and their acid-base properties were analysed by case-tailored evaluation methods. Macroscopic and microscopic protonation constants were determined, and the concomitant interactivity parameters were calculated. The species- and site-specific protonation constants are interpreted by means of inductive and shielding effects, also, in comparison with their sulfur containing analogues. The species-specific chemical shifts of these compounds show close correlation with the corresponding selenolate protonation constants. This relationship is observed and described for selenolates for the first time, and allows the prediction of selenolate oxidizabilities in important biomolecules.