There has been substantial recent interest in studying monolayer-protected gold clusters (MPCs) owing to their diverse applications. The present work is an electrochemical study of novel gold nanoparticles covered with a monolayer of mercapto-dodecanol ended chloro-dicyano-quinone (HS-C12O-CDQ), which was adsorbed on the electrode (CDQ-MPCs film). Our findings reveal a redox behavior for CDQ-MPCs film similar to the solution electrochemistry of dichloro-dicyano-quinone. Furthermore, a diffusion-like mechanism was found for electron transfer, which may have occurred due to proton diffusion towards or outwards the electrode through the film casted. Chronoamperometry confirmed diffusion behavior of the ET process. Finally, EIS was used to find the rate constant of ET process for the redox reaction that occurred and the contribution of MPCs in total interfacial capacitance.

the inhibitory behavior of Ponceau 4 R (an important industrial food dye) on the corrosion of copper surface in 3. 5% NaCl solution was studied using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and Fourier transform infrared (FT-IR) spectroscopy. Polarization curves indicated that the SELF-ASSEMBLED monolayer of Ponceau 4 R acts as a mixed inhibitor. The adsorption of inhibitors was well fitted to the Langmuir isotherm and the thermodynamic parameters (Kads, Δ G0) were also calculated and discussed. The inhibition efficiency of ponceau 4 R film reached 99. 5% under optimized conditions and the standard Gibbs energy of 31. 1 kJ/mol indicated that the adsorption mechanism of the SELF-ASSEMBLED monolayer of Ponceau 4 R on copper was a mixed mode of physical and chemical adsorption. The obtained results revealed that other food dyes containing functional groups such as hydroxyl, sulfonyl, aromatic rings and especially azo groups can act as green inhibitor for corrosion of copper in neutral sodium chloride solutions. Prog. Color Colorants Coat. 13 (2020), 199-212© Institute for Color Science and Technology.