Direct chemical functionalization of as-grown electroactive polypyrrole film containing leaving groups

A synthetic route for the functionalization of polypyrrole is described, which involves a direct chemical modification of as-grown polymer films containing labile groups, such as N-hydroxysuccinimide (NHS). Pyrrole is first substituted at the 3-position with NHS, and further electrochemically polymerized into a film of poly [3-NHS pyrrole]. A direct chemical substitution of the easily leaving group NHS by another functional group is then carried out on the polymer film. beta-Ferrocene ethylamine has been chosen as electrochemical probe, and the experimental conditions for substitution have been analyzed. Based on the ferrocene electroactivity, results show that substitution occurs with 100% yield on all the bulk of the polymer film, allowing the deposition of 10(-6) mol cm(-2) of electroactive ferrocene linked to polypyrrole. This new approach toward the functionalization of polyheterocycles opens the way for an easy realization of elaborate electroactive architectures, involving fragile and expensive chemical or biochemicals groups, such as oligonucleotides, enzymes or hormones showing recognition properties.