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 are studied in an aqueous solution by the pH-metric method. It is found 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 log K₁ and log K₂ are 8.27 and 0.65, respectively. Using the potential of a silver electrode, the equilibria of silver(I) complex formation with 1,2,3-benzotriazole are studied. The data obtained indicate that Ag⁺ replaces the hydrogen ions of the ligand molecule and forms AgBta and \({\text{AgBta}}_{2}^{ - }\) complexes with the stability constants log β₁ = 8.50 (AgBta) and log β₂ = 12.65 (\({\text{AgBta}}_{2}^{ - }\)).