New Generation of Diazonium based on Heterocyclic Amines : Electrochemical Investigations

This work is devoted to the study of the electrochemical grafting onto platinum ultramicroelectrode (UME) through diazonium electroreduction using a heteroaromatic compound, without phenyl groups. The grafting was performed using the electrochemical reduction of 2-aminoterthiophenyldiazonium cation, generated in situ. It leads to the attachment of an electroactive organic layer onto the UME surface. Following that the electrochemical response of the modified UME in the presence of various reversible redox couples shows that the attached layer acts as a conductive switch. It behaves as a barrier to electron transfer when the standard redox potential is below 0.5 V vs. SCE; in this case the oxidation wave of the redox probe is shifted to more positive values. However, for more oxidizing redox probes the layer can be considered as transparent and no barrier effect is observed. Finally, scanning electrochemical microscopy (SECM) can be performed using this electroswitchable modified platinum.