Molecular docking, theoretical calculations and potentiometric studies of some azo phenols

The ligands 5-amino-2-(phenyldiazenyl)phenol and its derivatives (HLn) were synthesized from the coupling of 3-aminophenol with aniline and its p-derivatives and characterized by different spectroscopic techniques. The molecular and electronic structures of the investigated compounds (HLn) were also studied using quantum chemical calculations. Molecular docking was used to predict the binding between azo compounds with the receptor of prostate cancer 2q7k-Hormone and 3hb5-oxidoreductase receptor of breast cancer. The proton-ligand dissociation constant of the azo compounds (HLn) and metal-ligand stability constants of their complexes with metal ions (Mn2 +, Co2 +, Ni2 + and Cu2 +) have been determined by potentiometric technique in 0.1 M KCl and 40% (by volume) DMF-water mixture. For the same ligand at constant temperature, the stability constants of the formed complexes increase in the order Mn2 +, Co2 +, Ni2 + and Cu2 +. The effect of temperature was studied at 303, 313 and 323 K and the corresponding thermodynamic parameters (∆G, ∆H and ∆S) were derived and discussed. The dissociation process is non-spontaneous, endothermic and entropic ally unfavorable. The formation of the metal complexes has been found to be spontaneous, endothermic and entropic ally favorable.