A preliminary study of cyclic voltammetry in glassy carbon electrode. Redox Behaviour of 2-Amino-4-phenylthiazoles

Abstract

In this work a voltammetric study of the reduction processes of five substituted 2-Amino-4-(4-X-phenyl) thiazoles (-X = -H, -OCH3, -CH3, -Cl, -NO2) in dimethylsulphoxido was performed. In the potential range considered (-2.0 to -2.9 V vs Ag+/AgCl), one signal (Ic) were detected, which was associated with the electrochemical reduction of the corresponding of the heterocycle compound. The voltammetric analysis at the reduction signal showed that when in-creasing the sweep speed (0.1 < v < 1.0 Vs⁻¹), an oxidation signal associated with the Ic wave was not observed. The linear dependence of the peak current with respect to the root of the velocity of the Ic wave, showed that this was a process controlled by diffusion and showed an apparently irreversible behavior. Peak potential shifted to more negative values as the potential sweep speed was higher; this was indicative of irreversible behavior in this signal. The substitution changes influenced the electrochemical behavior, evidencing that a substituent, as in this case methoxy group compound -OCH3, causes a greater energetic demand for the reduction of the thiazole derivative it becomes evident in the most negative potential, with respect to the derivative without substituent -H. This was new evidence of the behavior electrochemical of 2-Amino-4-(4-X-phenyl) thiazoles derivates which had not been reported for these compounds.