Electrochemical Behaviours of Substituted Thiophenes

No Thumbnail Available



Journal Title

Journal ISSN

Volume Title


Addis Ababa,University


The electrochemical oxidation of 3-methylthiophene, thiophene and 2',5'- dibtyloxy-3- phenylthiophene have been studied using plalinium, glassy carbon and gold electrodes in acetonitrile. Lithium perchlorate served as supporting electrolyte in all experiments. The oxidation of 3-methyl thiophene at different concentration was carried out on Pt, GC and Au electrodes using de cyclic voltammetry. As the concentration increases, a preadsorption peak was noted in all electrodes. It was seen that the PI electrode is more sensitive to the adsorpt ion of the product (radicals). The oxidation of 3- methylthiophene was also performed under potentiastatic conditions. It was observed that the current response decays with time at a rotating electrode. This shows that diffusion is not a rate determining step in the oxidation of 3-methylthiophene. The limiting charge passed on stationary and rotating Pt electrode was evaluated on the primary oxidation of 4.2 mmol L-1 3-methylthiophene on Pt electrode. Attempts were made to compare the charge passed with the theoretically charge expected from the monola/ er coverage of the electrode surface. The diffusion coefficient of ferrocene was determined on stationary Pt electrode. This value was compared with that of 3-methylthiophene and thiophene. The higher value of the diffusion coefficient of thiophene and 3-methylthiophene was due to a smaller molecular radius. In the electrochemical oxidation of 2',5'-dibutyloxy-3-phenylthiophene at least three anodic oxidation peaks were observed in both DC and AC cyclic voltammetry. The first peak potential occurred around 1.05 V, the second at 1.47 Vand the third around 1.91 V.



Electrochemical Behaviours