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ISSN 1998-9539

poly-Aminophenylporphyrin Film Formation Activated by Superoxide Anion Radical

Svetlana A. Chulovskaya, Sergey M. Kuzmin,@ and Vladimir I. Parfenyuk
G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, 153045 Ivanovo, Russian Federation
@Corresponding author E-mail:
Poly-5,10,15,20-tetrakis(4’-aminophenyl)porphyrin (poly-H2T(p-NH2Ph)P) films were obtained using dimethylsulfoxide solutions of porphyrin by electropolymerization during voltage scanning in the range of -2.0 to +1.2 V vs Pt quasi-reference electrode. Significant influence of dissolved oxygen on the film formation process was also demonstrated. It was shown that the shape position and amplitude of porphyrin redox peaks have unchanged under potential cycling in oxygen-free solutions. An irreversible peak corresponded to the formation of π-cation radical at positive area and reversible redox at negative. Poly-porphyrin film formation in oxygen-free DMSO was negligible. In contrast the shape position and amplitude of redox peaks of CV curve of oxygenated H2T(p-NH2Ph)P solution were changed during cycling. There were an irreversible oxygen electroreduction peak and the porphyrin peaks. It is well known that in DMSO media the oxygen electroreduction is quasi-reversible and leads to one-electron formation of superoxide anion radical (O2• –): О2 + ē → O2• –. The irreversibility of O2 electroreduction peak in the H2T(p-NH2Ph)P presence indicated an appearance of chemical reaction between O2• – and porphyrin. Additionally in oxygenated solution of H2T(p-NH2Ph)P during voltage scanning the golden color films were formed. The films were well coupled with the working electrode surface and were not soluble in water, ethanol and dichloromethane. The IR spectra of the coating have allowed us to determine the type of H2T(p-NH2Ph)P binding into poly-porphyrin films and to propose mechanism of its formation. First of all the hydrogen atom of aminophenyl substituents has passed to the superoxide anion, so the radicals of porphyrin are formed. Then the poly-porphyrin film were obtained via recombination of porphyrin radical.



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