Synthesis and characterization of Schiff base derivative with pyrrole ring and electrochromic applications of its oligomer

•2-[(1H-pyrrol-2-yl-methylene)amino]phenol was obtained by condensation reaction of 2-aminophenol and pyrrole-2-carbaldehyde.•The oligo-2-[(1H-pyrrol-2-yl methylene)amino]phenol was synthesized via oxidative polycondensation.•The metal complexes of oligomer were synthesized in methanol and THF mixture.•The copolymers of oligomer with thiophene, 3,4-ethylenedioxythiophene and pyrrole were electrochemically synthesized.

In this study, Schiff base monomer, 2-[(1H-pyrrol-2-yl-methylene)amino]phenol (2-PMAP) was obtained by condensation reaction of 2-aminophenol with pyrrole-2-carbaldehyde. This monomer was oxidized in an aqueous alkaline medium by NaOCl to obtain the corresponding oligomer (O-2-PMAP). The resulting compounds were characterized by 1H- and 13C-NMR, FT-IR, UV–vis, TG-DTA and size exclusion chromatography (SEC) techniques. Metal complexes compounds of O-2-PMAP were prepared with various metal salts, such as Cu (AcO)2·H2O, Zn (AcO)2·2H2O, Cd (AcO)2·2H2O, Pb (AcO)2·3H2O and Co (AcO)2·4H2O. In addition to this, electrochemical copolymerization of O-2-PMAP with thiophene (Th), 3,4-ethylenedioxythiophene (EDOT) and pyrrole (Py) were performed onto indium/tin oxide (ITO)-coated glass plate. The spectral changes of the co-polymeric films were recorded in the range of the different potentials. The film stabilities of its EDOT and Py copolymers were determined. Consequently, it was realized that the copolymer films kept their stability for a long time.

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