IN-SITU SPECTROSCOPIC INVESTIGATION OF THE ANODIC-OXIDATION OF 1,4-DIMETHOXYBENZENE AT PLATINUM-ELECTRODES

The electrooxidation of p-dimethoxybenzene on platinum electrodes in s trictly dried acetonitrile solutions was studied by in situ spectrosco pic methods (UV-Vis differential reflectance, FT-IR reflectance and el ectron spin resonance (ESR) spectroscopies). The UV-Vis and IR spectra allowed us to investigate the early stages of polymerization and to m onitor the film growth, as a function of the electrode potential and t he number of potential cycles. The use of both p- and s-polarized IR r adiations allowed us to observe the initial step of formation of the r adical-cation and its dimerization at the electrode surface or its dif fusion in solution. These observations were corroborated by ESR spectr oscopy, which showed clearly the participation of the monomer and olig omer radicals in the electropolymerization process. On the other hand, the monomer concentration is a very important factor for molecular or ientation at the electrode surface and formation of the polymer film.