A new metal-organic framework based on cadmium thiocyanate and 6-methylequinoline as corrosion inhibitor for copper in 1 M HCl solution

Faint green crystals of the metal organic framework (MOF) [Cd(SCN)(2)(6-mquin)(2)], 1, was obtained by the reaction of CdSO4.5H(2)O with 6-methylequinoline (6-mquin) in the presence of KSCN. 3Dnetwork structure was created via H-bonds and pi-pi stacking interactions. The structure of the MOF 1 was characterized by IR, H-1-NMR, UV-visible, TGA, and X-ray single crystal analysis. The structure of the MOF 1 consists of cyclic (CdSCN)(n) building blocks exhibiting chair conformation creating 1D-chain decorated by the coordinated 6-mquin on both sides. The 1D zig-zagchain is bonded to another chain by hydrogen bonds organizing these chains into a 2D layer. Furthermore, the 2D layers are interacted each other feathering three-3D metal organic framework containing cavities through face-to-face pi center dot center dot center dot pi interactions. The MOF 1 was tested as corrosion inhibitor for copper in 1 M HCl solution using potentiodynamic polarization and electrochemical impedance (EIS) techniques. Adsorption of the MOF 1 obeyed Langmuir adsorption isotherm. Effect of temperature on the corrosion process was studied and the activation parameters were calculated and discussed. The results obtained from the two different electrochemical techniques are in a good agreement.