Preparation, characterization and electrocatalytic performance of a novel poly(2,5-di(thienyl)pyrrole) modified electrode bearing TEMPO

A novel monomer 2,5-di(thienyl)pyrrole bearing TEMPO, 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)benzoyl-oxy-2,2,6,6-tetramethylpiperidin-1-yloxy (SNS-TEMPO) was synthesized. The corresponding polymer modified electrode (PSNS-TEMPO) was successfully prepared by cyclic voltammetry, and characterized by SEM, EDS, XPS and element mapping. For comparison, another novel monomer 4-(1H-pyrrol-1-yl)benzoyl-oxy-2,2,6,6-tetramethylpiperidin-1-yloxy (N-TEMPO) was synthesized and the corresponding polymer modified electrode (PN-TEMPO) was prepared. Introduction of thiophene unit on each side of pyrrole unit to extend the conjuga-tion chain length was propitious to make the electropolymerization of SNS-TEMPO easier. In addition, the elec-trocatalytic performance for electrooxidative self-coupling of benzylamine to N-benzylidenebenzylamine on PSNS-TEMPO was better than that on PN-TEMPO prepared under similar conditions. The possible reaction mechanism of benzylamine self-oxidation coupling reaction with PSNS-TEMPO was proposed.