Heterocyclic chelating agents. Part III. Metal complexes of 4-(2-pyridyl)thiazole and 2-(2-pyridyl)thiazole

Abstract

A study has been made of the metal complexes of 4-(2-pyridyl)thiazole (A) and 2-(2-pyridyl)thiazole (B) in aqueous solution at 25·0° and ionic background 0·1M in nitrate ions. The acid dissociation constants of the protonated species AH⁺ and BH⁺ have been measured and formation constants for the species MA²⁺, MA₂²⁺, and MA₃²⁺(M = Cu, Ni, Co, Fe, and Zn) and MB²⁺, MB₂²⁺, and MB₃²⁺(M = Cu, Ni, Fe, and Zn) have been calculated by a least-squares method from data obtained by potentiometric, spectrophotometric, and partition techniques. The results are compared with those previously reported for similarly constituted ligands.