S-acetyl-calix[8]arene adsorption on polycrystalline Au surface: A kinetic study

Cyclic voltammetry (CV), Raman spectroscopy (RS), quartz crystal microbalance (QCMB) and electrochemical impedance spectroscopy (EIS) measurements were carried out in order to investigate the kinetics of the S-acetyl-calix[8]arene (S-Calix) adsorption, the structure of the layer formed on polycrystalline Au surface and its stability. The CV response recorded at Au/S-Calix modified electrode revealed an unusual time evolution of the surface coverage. The RS data corroborated with those provided by QCMB measurements proved the existence of multiple SAu bonds in the structure of the S-Calix monolayer. The EIS was used to rationalize the kinetics of the monolayer formation and its reorganization. It was established that, due to the high affinity existing between the S and Au atoms and the remarkable flexibility of the calix[8]arene skeleton, the reorganization process consists in the increase of the number of SAu bonds for the already adsorbed S-Calix molecules.