Main Strategies for the Synthesis of meso-Arylporphyrins

meso-Arylporphyrins as most accessible tetrapyrrole macroheterocycles have always been the focus of attention from researchers concerned with practically useful properties of these compounds. The first syn­theses of meso-arylporphyrins date back to about 90 years ago. Up to now, the yields of these compounds have been improved from 5 to 80%. The present review analyzes different ways and strategies for the synthesis of meso-aryl-substituted porphyrins. The most efficient methods that can be scaled up to an industrial level have been identified.

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.

An electrochemical quartz crystal microbalance study of 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin electropolymerization process

The process of 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin electropolymerization has been studied by the quartz crystal microbalance method in different electrodeposition conditions. The films were deposited in two modes: in potentiostatic conditions (at the potential of [Formula: see text]2 V) and in potentiodynamic conditions (CV with the potential scan rate of 20 mV/s). The effect of electrolysis parameters on 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin electropolymerization has been studied by obtaining films in two modes and using two supporting electrolytes: tetrabutylammonium perchlorate or tetrabutylammonium hexafluorophosphate. The biggest film mass gain was observed on a clean electrode surface. At further film deposition on the polyporphyrin-coated electrode, the film mass growth stopped. The electrodeposition effectiveness was somewhat higher in the potentiodynamic conditions, with the formation of a looser film. The nature of the supporting electrolyte did not have a significant effect on the electrodeposition process. A significant contribution to the deposition was made by the electrode material. The film thickness was 25–80 nm. The films possessed [Formula: see text]-type conductivity; and the flat-band potential for poly-H[Formula: see text]T(4-OHPh)P obtained in potentiodynamic conditions was 0.33 V, for poly-H[Formula: see text]T(4-OHPh)P obtained in potentiostatic conditions it was 0.16 V.