The results of studying the spectral properties of zinc and cobalt meso-tetraphenyl-porphyrins included as the modifiers in polymethylmethacrylate, polystyrene and polyvinylchloride films are presented in this article for the first time. It was established that an inert polymer matrix of polyvinylchloride, block polystyrene and polymethylmethacrylate does not affect the spectral properties of tetrapyrrole macroheterocycles, which are included in it. In this case, insignificant bathochromic shift of the absorption bands of the metal complexes in the modified films is recorded, which is probably due to the presence of intermolecular interaction of the metalloporphyrin with the polymer matrix. The method of polymer producing is important for modification of polystyrene or polymethyl methacrylate films. The ignificant changes are observed in the electronic spectra of metalloporphyrins due to the interaction between the modifier and the residual amount of the radical polymerization initiator (benzoyl peroxide) used in the preparation of polymers. Earlier studies showed that the interaction of benzoyl peroxide with zinc and cobalt meso-tetraphenylporphyrinates in solution leads to the formation of the corresponding metalloisoporphyrinates. In this work, the possibility of such structures formation in a polymer matrix is shown for the first time. In this case, in the electronic absorption spectra of the modified films, as in solutions, bands appear in the near IR region. The fluorescent properties of modified films have been studied. It was shown that in the absence of interaction between the components in the film, metalloporphyrins introduced into the polymer matrix retain their ability to fluorescence.
The article presents the results of the kinetics study of the cobalt porphyrins interaction with radical polymerization initiators – benzoyl peroxide and lauryl peroxide – in solution by the spectrophotometric method. From disparate literature data, it is known that some metalloporphyrins can interact with benzoyl peroxide to form the tautomers of porphyrins – isoporphyrins. These compounds have a number of specific properties, for example, it can be catalysts of various processes. Perhaps the isoporphyrins formation is the reason for high activity of the initiating systems “cobalt porphyrin – benzoyl peroxide” in the polymerization of vinyl monomers. Cobalt(II)complexes of tetraphenylporphyrin, tetra-para-methoxyphenylporphyrin, 5,15-bis(4´-tert-butylphenyl)-3,7,13,17-tetramethyl-2,8,12,18-tetra-p-butylporphyrin were selected as the objects of this study. The influence of the porphyrin ligand structure on the formation of cobalt isoporphyrins was estimated. The interaction of cobalt (II) tetraphenylporphyrin and cobalt (II) tetra-para-methoxyphenylporphyrin with peroxides showed changes in the electronic absorption spectra of metalloporphyrins: deformation of the Soret band, reduction of the absorption band in the visible region, and the appearance of absorption bands in the near IR region. These changes are characteristic for metalloisoporphyrins. Data on the interaction of cobalt porphyrins with lauryl peroxide were obtained for the first time. The formation of isoporphyrins is possible with the different ratio of concentrations of reagents: with a lack of peroxide, with equimolar ratio, and also with a significant (100-fold) excess of peroxide. When 5,15-bis (4´-tert-butylphenyl)-3,7,13,17-tetramethyl-2,8,12,18-tetra-p-butylporphyrinate cobalt (II) reacted with peroxides, no isoporphyrinates were observed. The article presents the effective reaction rate constants of the cobalt isoporphyrinates formation at 25 °C. It is shown that the structure of both cobalt porphyrinates and organic peroxides affects the possibility and rate of isoporphyrins formation.
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