Surface functionalization of ferrocene based ionic liquid onto carbon surface using stepwise grafting

• Oxidative grafting onto carbon electrode.
• Aryl diazonium layer attached onto carbon electrode.
• Over-grafting of ferrocene based ionic liquid.
• Immobilization of ionic liquid cation.

The immobilization of ferrocene based ionic liquid onto carbon electrode using stepwise procedure has been investigated. Firstly, the oxidative grafting onto carbon electrode of 2-(4-aminophenyl)acetic acid in electrolytic solution containing sodium nitrite and perchloric acid has been performed. As a result, a thin organic layer bearing aryl diazonium was attached onto carbon electrode. Secondly, further functionalization has been performed using the reactivity of aryl diazonium end group without applying any external potential. Thus, after the addition of ferrocene based ionic liquid it undergoes a Gomberg arylation to form a new biaryl compound through the rapid reduction of diazonium end group. The electrochemical investigations exhibit the presence of ferrocene redox signal highlighting the attachment of ferrocene imidazolium onto carbon electrode. Moreover, similar procedure was successfully achieved onto carbon ultramicroelectrode. As an important result, the generated layer exhibits ionic mobility and leads to construct a new class of ionic liquid/electrode interface.

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