Geometrical structure, molecular docking, potentiometric and thermodynamic studies of 3-aminophenol azodye and its metal complexes

The proton-ligand dissociation constants of 4-(2,3-dimethyl-1-phenylpyrazol-5-one azo)-3-aminophenol (HL) and its metal stability constants with Mn(II), Co(II), Ni(II) and Cu(II) ions have been determined using potentiometric studies. The molecular structure of the ligand is optimized theoretically and the quantum chemical parameters are calculated. The proton-ligand dissociation constants of HL and its metal stability constants with Mn(II), Co(II), Ni(II) and Cu(II) have been determined potentiometrically. The potentiometric studies were carried out in 0.1 M KCl and 20% (by volume) DMF-water mixture. At constant temperature the stability constants of the formed complexes decrease in the order of Cu(II) > Ni(II) > Co(II) > Mn(II). The effect of temperature was studied at 298, 308 and 318 K and the corresponding thermodynamic parameters (ΔG, ΔH and ΔS) were derived and discussed. The dissociation process is non-spontaneous, endothermic and entropically unfavorable. The formation of the metal complexes has been found to be spontaneous, endothermic and entropically favorable. Molecular docking was used to predict the binding between azodye ligand and the receptor of prostate cancer mutant 2q2k-Hormon and receptor of breast cancer mutant 3hb5-Oxidoreductase.