COMPLEX FORMATION OF SILVER(I) WITH 1,2,3-BENZOTRIAZOLE. PROTONIZATION CONSTANTS OF 1,2,3-BENZOTRIAZOLE

Abstract

The acid–base properties of 1,2,3-benzotriazole (Bta) at 25 °C and I = 0.1 mol/l KCl were studied by the pH-metric method in an aqueous solution. It has been established that in the strongly acidic region of the solution, one of the two nitrogen atoms of the pyridine type of the Bta triazole rings undergoes protonation, and at high pH values, hydrogen abstraction occurs from the NH fragment of the molecule. The obtained values of the protonization constants of 1,2,3-benzotriazole are: log K1 = 8.27 and log K2 = 0.65. Using the potential of a silver electrode, the equilibria of silver(I) complexation with 1,2,3-benzotriazole were studied. The data obtained indicate that Ag+replaces the hydrogen ions of the ligand molecule and forms complexes of the following composition AgBta and AgBta2– with stability constants equal to log β1 = 8.50 (AgBta) and logβ2 = 12.65 (AgBta2–), respectively.