Bis- and tris-amino-substituted tetraphenylporphyrins. Comparative electrochemistry, film formation and ORR response of the films in alkaline media

The paper analyzes how the structure of porphyrin affects its electrochemical characteristics, film formation process and physicochemical properties of the obtained materials. A comparison of the redox processes of 21H,23H-5,15-bis-(4-aminophenyl)-10,20-di-phenyl porphyrin (Porph I) and 21H,23H-5,10,15-tris-(4-amino-phenyl)-20-phenyl porphyrin (Porph II) shows that Porph I is more stable in oxidation and less stable in reduc-tion processes than Porph II. The presence of electrochemically active amino groups in the composition of the porphyrin molecules allows the superoxide-assisted electrochemical deposition method to be applied to suc-cessfully form poly-Porph I and poly-Porph II films from dimethyl sulfoxide solutions. Spectral methods con-firm that the obtained materials preserve their porphyrin structure. The structure of the initial monomer molecules is demonstrated to affect the film formation and surface morphology of the prepared materials. Oxygen electroreduction in an alkaline medium is shown to have smaller kinetic limitations on poly-Porph II films than that on poly-Porph I ones.

Automated summary

The paper investigates the influence of porphyrin structure on its electrochemical characteristics, film formation process, and physicochemical properties. The comparison between Porph I and Porph II reveals that Porph I exhibits higher stability in oxidation but lower stability in reduction processes than Porph II. By utilizing the electrochemically active amino groups in the porphyrin molecules, poly-Porph I and poly-Porph II films are successfully formed using the superoxide-assisted electrochemical deposition method. Spectral methods confirm the preservation of the porphyrin structure in the obtained materials, while the structure of the initial monomer molecules affects the film formation and surface morphology. Moreover, oxygen electroreduction in an alkaline medium demonstrates smaller kinetic limitations on poly-Porph II films compared to poly-Porph I films.