Potentiometric studies of metal Complexes of 4-(4-nitrophenylazo) resorcinol (magneson) with Co(II), Cu(II), and Zn(II) ions in mixed solvent

Abstract

In this research work, the acid dissociation constants of 4-(4-nitrophenylazo) resorcinol = L1 and the formation constant of the metal chelates formed by this ligand with Co(II), Cu(II), and Zn (II) have been determined Potentiometrically at 288K in 75% ethanol-water mixture at 0.1M KNO3 ionic strength against 0.1 M KOH. The stability constants of metal complexes were detected at different temperatures. The thermodynamics parameters such as ΔG, ΔH and ΔS of binary complexes were determined using the Vant-Hoff equations to measure the effect of temperature on the stability of 4-(4-nitrophenylazo) resorcinol complexes with metal ion. The influence of solvents on the free ligand and their metal complexes have been determined and discussed