New Generation of Diazonium based on Heterocyclic Amines : Electrochemical Investigations

Abstract

This work is devoted to the study of the electrochemical graftingonto platinum ultramicroelectrode (UME) through diazoniumelectroreduction using a heteroaromatic compound, without phenylgroups. The grafting was performed using the electrochemicalreduction of 2-aminoterthiophenyldiazonium cation, generated insitu. It leads to the attachment of an electroactive organic layeronto the UME surface. Following that the electrochemicalresponse of the modified UME in the presence of variousreversible redox couples shows that the attached layer acts as aconductive switch. It behaves as a barrier to electron transfer whenthe standard redox potential is below 0.5 V vs. SCE; in this casethe oxidation wave of the redox probe is shifted to more positivevalues. However, for more oxidizing redox probes the layer can beconsidered as transparent and no barrier effect is observed. Finally,scanning electrochemical microscopy (SECM) can be performedusing this electroswitchable modified platinum.