Structure, Characterization and Anti-Corrosion Activity of the New Metal–Organic Framework [Ag(qox)(4-ab)]

Yellow crystals of the metal–organic framework (MOF), [Ag(qox)(4-ab)] ( 1 ) were obtained at room temperature by the reaction of AgNO 3 , quinoxaline (qox) and 4-amino benzoic acid (4-aba). A cluster molecule containing two silver atoms, two qox and two 4-ab ligands is considered the basic building block of the structure of 1 . A 3D-network structure is created via H-bonds and π–π stacking. MOF 1 was tested as a corrosion inhibitor for C-steel in 1 M HCl solution using potentiodynamic polarization and electrochemical impedance techniques. It was found that 1 is rich with electron donating groups and the π-systems exhibiting high inhibition efficiency. The adsorption of 1 obeyed the Freundlich adsorption isotherm. Polarization curves indicate that 1 is mixed-type inhibitor. Activation parameters were calculated and discussed. The results obtained from EIS and potentiodynamic polarization are in good agreement.