Electrochemical study of acid-base properties of some 2,5-dihydro-1,3,4-thiadiazoles in aqueous-ethanolic solutions

摘要

The dissociation constants K-a for spherically crowded 2'- and 2,5-substituted thiadiazolines and their protonated forms in 45% (v/v) aqueous-ethanolic solutions (ionic strength m = 0.1) were determined using the pH-metric method. All the thiadiazoles are weak bases. Some of them showed also weak acidic properties. The formation enthalpies have been calculated using the MNDO method. On the basis of the obtained results the mechanism of the protonation process is discussed. [References: 34]