Polyporphyrin Films Research Articles

Cu-porphyrin-based polymers in electroreduction reactions of gases

In this work, the electrochemical properties of Cu-complexes of di- and tri-amino-substituted tetraphenylporphyrins in dichloromethane were investigated by the cyclic voltammetry method. Electrooxidation of porphyrins in a dichloromethane solution produced polyporphyrin films on the electrode. The formation of polymers occurs through the amino groups of phenyl substituents with the generation of phenazine and dihydrophenazine fragments. The surface morphology and thickness of polyporphyrin films were studied using a scanning electron microscope. The surface of the poly-Cu5,15-di(4′-aminophenyl)-10,20-diphenylporphyrin film is a network of fibers of about 5 µm long and 0.2–0.3 µm thick. The film thickness is 14 µm. The surface of poly-Cu5,10,15-tri(4′-aminophenyl)-20-phenylporphyrin has large branched agglomerates of indefinite shape; the film thickness is 22 µm. The catalytic activity of the obtained polyporphyrin films in oxygen and carbon dioxide electroreduction reactions were evaluated. Poly-Cu5,10,15-tri(4′-aminophenyl)-20-phenylporphyrin was found to be more catalytically active in both reactions, which is evidently associated with a more developed surface of the polymer.

Electrochemically produced films based on individual porphyrins and bimetallic composites: Morphology and electrocatalytic properties in the reaction of oxygen electroreduction

In this work, we obtained polyporphyrin films based on Fe(III)Cl-5,10,15,20-tetrakis(4-pyridyl)porphyrin and Mn(III)acetate-5,10,15,20-tetrakis(4-pyridyl)porphyrin and composite films on their basis by electrooxidation-induced electrochemical polymerization. The obtained films produced uniform coatings. Spectral analysis showed that the composite films were enriched with iron complexes. Comparative analysis of the prepared films demonstrated differences between the morphologies of the composite film and films of individual metal complexes. The oxygen electroreduction process on the obtained materials proceeded at more positive values than that on carbositall. The effective number of transferred electrons demonstrated that replacing catalysts based on individual porphyrins with the bimetallic composite changed the process mechanism: while the four-electron mechanism competed with subsequent two-electron reactions on the Fe(III)Cl-5,10,15,20-tetrakis(4-pyridyl)porphyrin and Mn(III)acetate-5,10,15,20-tetrakis(4-pyridyl)porphyrin films, on the bimetallic composite the process mainly represented a four-electron reaction.

FORMATION FEATURES AND ELECTROCHROMIC PROPERTIES OF POLYPORPHYRIN FILMS BASED ON Zn-TETRAKIS(3-(HYDROXYPHENYL)PORPHYRIN

This paper presents the results of electrochemical deposition and the redox behavior of polyporphyrin films based on Zn(II) tetrakis(3–(hydroxyphenyl)porphyrin (ZnT(3–OHPh)P). It has been shown that electrochemical deposition initiated by superoxide anion–radical can be used to form films based on ZnT(3–OHPh)P. The potential ranges at which the electrochemical deposition of poly–ZnT(3–OHPh)P occurs on ITO electrodes were determined. The thickness of the obtained films based on ZnT(3–OHPh)P was determined by atomic force microscopy (AFM) and is about 90 nm. The presented results of studying the electronic absorption spectra of films based on ZnT(3–OHPh)P showed that the tetrapyrrole macrocycle is not destroyed during electrochemical deposition. The paper presents the results of Raman spectroscopy, which confirm that the main reason for the binding of hydroxyphenylporphyrin molecules in a polyporphyrin film is the formation of C–O–C bridges between side substituents. The redox processes in poly–ZnT(3–OHPh)P were studied by the spectroelectrochemical method. Electrochromic responses of films based on ZnT(3–OHPh)P have been determined in a wide range of potentials. Process of electroreduction leads to a decrease and a shift to the short–wavelength region of the Soret band. Electrooxidation of films based on ZnT(3–OHPh)P leads to a decrease in the intensity of the Soret band and the disappearance of the Q bands. It is shown that the observed spectral changes are in good agreement with the known literature data and indicate the localization of excess negative or positive charges on the macrocycle. Due to the change in their optical properties depending on the applied voltage, films based on ZnT(3–OHPh)P can be recommended as a promising electrochromic coating.

Electrochemical synthesis and properties of polyporphyrin films based on 5,10,15,20-tetra(4-pyridyl)porphyrin

Polyporphyrin films were obtained by electrooxidative polymerization of 5,10,15,20-tetra(4-pyridyl)porphyrin which, in turn, was obtained by condensation of pyrrole with pyridine-4-carboxaldehyde. The polymer formation involved the side substituents, with the π-conjugated porphyrin platform being preserved. The obtained polyporphyrin forms an electroconductive coating possessing semiconductor properties with the band gap of 1.76 eV

Electrochromic properties of conductive polyporphyrin films based on 5,10,15,20-tetrakis(4-aminophenyl)porphyrin and 5,10,15,20-tetrakis(4-pyridyl)porphyrin

Polyporphyrin films based on 5,10,15,20-tetrakis(4-pyridyl)porphyrin and 5,10,15,20-tetrakis(4-aminophenyl)porphyrin were obtained by electrochemical polymerization during the electrooxidation of the respective monomers. The polyporphyrin formation involved the side substituents, with the [Formula: see text]-conjugated porphyrin platform being preserved. The obtained polyporphyrins form uniform electroconductive coatings, tightly adhered to the electrode surface. The electrochromic properties were studied by the spectroelectrochemical method. Electronic absorption spectra of the films were recorded under the action of electric current at the stepwise potential changes within several intervals. The obtained polyporphyrin films were shown to possess electrochromic properties. The films were oxidized when exposed to anodic potentials and reduced when exposed to cathodic potentials. The electronic absorption spectra were used to calculate the optical band gap of the initial, oxidized and reduced films and to evaluate their conductivity. The highest conductivity was found in the electrochemically oxidized poly-5,10,15,20-tetrakis(4-aminophenyl)porphyrin film.

Scan rate effect on superoxide-assisted electrochemical deposition of 2H-5,10,15,20-tetrakis(3-aminophenyl)porphyrin films

In this study, we apply the superoxide-assisted electrochemical deposition method to obtain polyporphyrin films based on 2Н-5,10,15,20-tetrakis(3-aminophenyl)porphyrin from dimethylsulfoxide solutions. It is shown that changes in the potential scan rate affect the film formation efficiency and surface morphology of electrodeposited polyporphyrin films. Poly-2H-5,10,15,20-tetrakis(3-aminophenyl)porphyrin films prepared at a given deposition time in low formation efficiency conditions are thinner and smoother. Surface morphology has a considerable effect on the functional properties of a material and scan rate variations can be considered a control parameter for adjusting the formation process to the film target functional application.

Electrodeposition of films of individual 5,10,15,20-tetrakis(3-aminophenyl)porphyrin metal complexes and their composite for electrocatalytic oxygen reduction

Carbon-based materials are common and quite promising for such industrial applications as power generation using electrochemical and electrocatalytic processes and can be successfully used as electrode substrates. The effectiveness of carbonaceous materials can be improved by modifying the electrode surface with phthalocyanine and porphyrin metal complexes possessing electrocatalytic properties. In this work, polyporphyrin films were obtained on a glassy carbon electrode from individual 5,10,15,20-tetrakis(3-aminophenyl)porphyrin metal complexes and a composite of two Fe and Mn metal complexes. The polymerization was carried out by the electrochemical method. The results of the evaluation of the polyporphyrin catalytic activity in oxygen electroreduction reactions achieved by different methods are in good agreement with each other and indicate higher catalytic activity of the composite of the two metal complexes than the films of individual porphyrins, which indicates the synergistic effect.

Supercapacitor electrodes based on electropolymerized protoporphyrins

The delocalized π-electrons on the tetrapyrrole ring allow efficient electron transport properties of porphyrins so that they can serve as electrode materials in energy storage devices. We demonstrate a pair of natural chlorophyll-related protoporphyrins, namely protoporphyrin IX (Por) and Mn (III) protoporphyrin IX chloride (MnPor), as the precursors to prepare polyporphyrin (PolyPor and PolyMnPor) films through the electrochemical coupling of the vinyl groups on the porphyrin macrocycles. The extension of the π-conjugated backbone lengthens the intramolecular channel of electrons and allows the electron transporting in higher speed, leading to an excellent electrochemical performance. Under 100 cyclic voltammogram cycles of polymerization, single-layered PolyPor gives capacitance of 93 F g−1, whereas laminar structure PolyMnPor provides significantly higher capacitance of up to 135 F g−1 with an expanded potential window. The well-aligned layer structure effectively accelerating the diffusion of electrolyte ions and enabling more accessible two-dimensional nanochannels furtherly promotes the electrochemical performance. Besides, we also optimize PolyMnPor synthesis condition; larger mass loading and higher capacitance of 250 F/g are achieved. These remarkable results demonstrate polyprotoporphyrins are promising and potential candidates as organic electrode materials. This study could direct future development of cost-effective energy storage devices based on naturally abundant biomaterials.

Electrochemical doping and semiconductor properties of poly-5,10,15,20-tetrakis(p-aminophenyl)porphyrin films

Poly-5,10,15,20-tetrakis([Formula: see text]-aminophenyl)porphyrin films were obtained by interfacial polymerization and electropolymerization. According to the results of electron spectroscopy and IR spectroscopy it has been determined that oxidative polymerization of 5,10,15,20-tetrakis([Formula: see text]-aminophenyl)porphyrin, regardless of its type (chemical/electrochemical), proceeds through the formation of phenazine and dihydrophenazine fragments. It has been established that the film obtained by the electrochemical method is in the oxidized state, the supporting electrolyte anions are included in the film. The polyporphyrin films obtained by interfacial polymerization are non-conductive. As a result of doping the films obtained by the chemical method, due to the oxidation in the anodic potential region, the polymer acquires [Formula: see text]-type semiconductor properties. It has been shown that electrochemical doping of poly-5,10,15,20-tetrakis([Formula: see text]-aminophenyl)porphyrin films can make them electroconductive. The obtained films can be recommended as elements of photovoltaic devices, the operation of which is based on the excitation of excitons under the action of light radiation, the redistribution of which leads to a change in the potential of the working electrode.

Влияние природы мономера на процессы электрополимеризации и физико-химические свойства пленок на основе гидрокси-замещенных тетрафенилпорфиринов

The ability to oxidatively polymerization from a solution in ethanol of tetraphenylporphyrin derivatives: 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin, 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin, Zn-5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin, Zn-5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin were studied. The polymerization of 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin does not occur; three of the four studied porphyrins form thin transparent polyporphyrin films tightly adhered to the electrodes surface. The influence of the nature of the monomer, the deposition mode, and the supporting electrolyte used on the process of electropolymerization and the properties of the deposited polyporphyrin films were studied. The spectral changes observed during the deposition of the films indicate that the generation of the polyporphyrin films occurs through the formation of C–O–C bonds and the keep of the porphyrin macroheterocycle in polyporphyrin.

Electrochemical Synthesis of Conducting Polyporphyrin Films based on 5,10,15,20-Tetrakis(4-hydroxyphenyl)porphyrin

A hydroxy-substituted tetraphenylporphyrin was oxidatively electropolymerized from its solutions in ethanol by cyclic voltammetry. The electropolymerization process is investigated using cyclic voltammetry, absorption spectroscopy, and electrochemical quartz crystal microbalance. The results of IR and electronic absorption spectroscopy studies show that, in deposition from ethanol, the polymerization occurs via the O−H group of the phenyl substituent, which results in the formation of C−O−C bonds. The mechanism of polyporphyrin formation is similar to polymerization of simple organic compounds. The deposited polyporphyrin film (thickness of 80 nm) has a smooth surface. Using the Mott−Schottky approach, it was establish that the films have hole conductivity (i.e., they are a p-type semiconductor). The flat band potential of the poly-5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin is 0.33 V. The film is further oxidized in a supporting electrolyte solution by applying positive potentials, with anions of the supporting electrolyte incorporating into the polyporphyrin.

Enhancement of photocurrent by incorporation of Preyssler type polyoxometalate protected nanoparticles in polyporphyrin films.

The introduction of nanoparticles (MNPs) at the surface of cationic poly-porphyrin films, obtained by electrostatic interaction between the bis-porphyrin copolymer and the Preyssler type polyoxometalate P5W30@MNPs, enhances the photocurrent (up to 2.5-3 times greater as a function of the used nanoparticle).

Highly conductive polyporphyrin films obtained by superoxide-assisted electropolymerization of para – aminophenyl porphyrin

The process of deposition of 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (H2T(4-NH2Ph)P) electopolymer films induced by superoxide anion radical in dimethyl sulfoxide (DMSO) has been studied. By the methods of electrode impedance spectroscopy and atomic-force microscopy it has, for the first time, been proved that it is possible to form a poly-H2T(4-NH2Ph)P film in DMSO in potentiostatic conditions at oxygen electroreduction potentials. Charge transfer through the poly-H2T(4-NH2Ph)P film has been characterized by modeling electrochemical impedance spectroscopy (EIS) data. It has been shown that in potentiostatic conditions, the formation of a poly-H2T(4-NH2Ph)P film induced by superoxide anion radical consists of at least two stages. At the first stage, the resistance of the surface film changes insignificantly, and at the second one it increases approximately linearly over time. Using the vibrational spectroscopy we have determined the type of binding of monomer fragments in the polyporphyrin film. The morphology and thickness of the deposited polyporphyrin films have been studied by the methods of atomic force microscopy. Based on the resistance and thickness estimates, we have determined the value of specific conductivity of the obtained film (about 4.2•10−4 S cm−1). The metal-free aminophenyl porphyrin electopolymer was also successfully tested as an electrocatalyst for the oxygen reduction reaction.

Physical and Chemical Properties of Polyporphyrin Films Based on the Mn Complexes of Amino-Substituted Tetraphenylporphyrin

The article presents the results of the study of electrochemical deposition and the physicochemical properties of polyporphyrin films deposited on glassy carbon, platinum, and ITO electrodes. Electropolymerization of Mn(III) 5,10,15,20-tetrakis(3-aminophenyl)porphyrin chloride from different solvents and in different deposition modes is carried out. In the process of electrooxidation of porphyrin monomer in solutions of dichloromethane and ethanol, polyporphyrin films are formed on the working electrode in the potential range from 0 to +2 V. The electropolymerization process is studied using the quartz microbalance method. The physicochemical properties of the films are studied using various methods: UV-VIS spectrophotometry, IR spectroscopy, scanning electron microscopy, atomic force microscopy, photo-EMF method. The number of electrons participating in the electropolymerization process is determined. Spectral methods show that a porphyrin structure is retained in the film, and in the process of electropolymerization, it is possible to incorporate μ-oxodimers into the composition of the film. It is found that the obtained polyporphyrin films possess semiconductor properties.

Superoxide-assisted electrochemical deposition of semiconductor polyhydroxyphenylporphyrin films

The method of superoxide-assisted electrochemical deposition was employed for the formation of film materials based on hydroxyphenylporphyrins and their metal complexes. The C–O–C bridges were the major moieties for bonding porphyrins inside the electropolymer. The obtained polyporphyrin films demonstrated a hole type of conductivity, which makes them suitable for various applications.

Влияние режима осаждения на полупроводниковые свойства порфириновых пленок

Влияние режима осаждения на полупроводниковые свойства порфириновых пленок

Modification of the surface of electrodes by polyporphyrin films for electrocatalytic reduction of oxygen

Modification of the surface of electrodes by polyporphyrin films for electrocatalytic reduction of oxygen

Electrodeposition and Characterization of Polyporphyrin Films Based on Mn Complexes of Amino-substituted Tetraphenylporphyrins

Electrodeposition and Characterization of Polyporphyrin Films Based on Mn Complexes of Amino-substituted Tetraphenylporphyrins

Electrodeposition of catalytically active polyporphyrin films of metal complexes of amino-substituted tetraphenylporphyrins

The process of electrodeposition of polyporphyrin films based on amino-substituted tetraphenylporphyrins and their metal complexes (CuT([Formula: see text]-NH[Formula: see text]Ph)P, FeClT([Formula: see text]-NH[Formula: see text]Ph)P, MnClT([Formula: see text]-NH[Formula: see text]Ph)P) has been studied by the quartz crystal microbalance method. The surfaces of the films have been characterized by the scanning electron microscopy method and the number of electrons taking part in porphyrin electropolymerization has been determined. It has been established that the most intensive film growth is observed for the metal-free porphyrin ligand. The obtained polyporphyrin films have been analyzed for the catalytic ability in oxygen electroreduction reactions.

Superoxide-assisted electrochemical deposition of Mn-aminophenyl porphyrins: Process characteristics and properties of the films

Electrochemical behavior and superoxide-assisted electrochemical deposition of Mn(III)chloride 5,10,15,20-tetrakis(meta-aminophenyl)porphine (MnClT(m-NH2Ph)P) and Mn(III)chloride 5,10,15,20-tetrakis(para-aminophenyl)porphine (MnClT(p-NH2Ph)P) in DMSO solutions on electrodes of various types have been investigated. It is shown that a surface film is formed in the oxygen electroreduction potentials region. The influence of the amino group position in the phenyl substituent on the deposition kinetics of the film and its morphology is demonstrated. It has been shown that the main motif of the porphyrin-porphyrin bond is phenazine type bridges, if the aminophenyl-porphyrin film is deposited by the developed method. A mechanism has been proposed for forming these bridges for the case of superoxide-assisted electrochemical deposition of poly-Mn-aminophenyl porphyrins films. It has been established that polyporphyrin films obtained from solutions of MnClT(m-NH2Ph)P and MnClT(p-NH2Ph)P in DMSO are electrocatalytically active in the reaction of oxygen electroreduction in an alkaline medium.