Preparation, chemical characterization, and electronic spectra of 6-(2-pyridylazo)-3-acetamidophenol and its metal complexes

The stereochemistry of new iron(III), cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) complexes of 6-(2-pyridylazo)-3-acetamidophenol (H2L) is studied on the basis of their analytical, spectroscopic, magnetic, thermal and conductance data. The dissociation constant of the ligand as well as the stability constants of its metal complexes have been determined spectrophotometrically. On the basis of the infrared spectra the coordination behaviour of the ligand to the metal ions is investigated. Magnetic susceptibility and solid reflectance spectral measurements are used to infer the structure. The prepared complexes are found to have the general formulae [M(HL)(H2O)(x)](A) . yH(2)O (M = Cu(II), Zn(II), Cd(II) and Fe(III); HL = 6-(2-pyridylazo)-3-acetamidophenolate; A = acetate in case of Cu(II) and Zn(II) or chloride in case of Cd(II) and Fe(III), x = 1-3 and y = 0-5) or [M(H2L)(H2O)(x)]Cl-2 . yH(2)O (M = Ni(II) and Co(II); H2L = 6-(2-pyridylazo)-3-acetamidophenol, x = 3 and y = 5-6).