We studied the reactions of sterically hindered bis-semiquinonates of copper(II) with 4,4′-bipyridine. Coordination polymer consisting of metallamacrocyclic binuclear copper(II) cage-like moieties bridged with 4,4′-bipyridine linkers was isolated in the reaction of copper(II) bis-semiquinonate metallamacrocycle with 4,4′-bipyridine. It is important that the initial and final metallamacrocycles in this reaction are different by the disposition of semiquinone units in the coordination surroundings of copper (II) ions. The transformation of one metallamacrocycle into another could only be achieved by a two-fold sequential cleavage of the metal-semiquinone bond.

The study of a binuclear copper complex, bearing a cage-like architecture, and obtained by self-assembly from a ditopic di-o-quinone ligand containing bulky substituents in the linker, showed that the exchange interactions characteristic of biradical forms of the free ligand are fully manifested in the obtained complex. The energy of the exchange interactions changes depending on the volume of the substituents that limit rotational vibrations around the linker bonds.

The immobilization of fluorinated tetraphenylporphyrins in the matrix of the sulfocathionite perfluorinated copolymer MF-4SK and the photosensitized oxidation of the cholesterol in the presence of the obtained composite are carried out in the supercritical (SC) carbon dioxide medium. It is shown that the reaction proceeds with the formation of 6-formyl-B-norchlorestane-3β,5β-diol (a potential antitumor agent), in contrast to the homogeneous photooxidation of cholesterol, where the main product is 7α-hydroperoxide-3β-hydroxy-chlorest-5-ene. A reaction mechanism is proposed, which assumes the process takes place inside the “ion channels” of MF-4SK.

Water-insoluble photosensitizing (PS) systems active in the generation of singlet 1 O 2 oxygen are obtained by immobilizing fluorinated tetraphenylporphyrin (FTPP) from a solution in acetone on films of polyelectrolyte complexes based on sodium alginate (SA) and chitosan (CT), and on solid water-insoluble gels of alginate and chitosan. The obtained polymer PS systems are used to establish the intensity of the photoluminescence of singlet oxygen in D 2 O and the activity of the photocatalytic oxidation of tryptophan in water. It is shown that the photocatalytic activity in the tryptophan oxidation of fluorinated tetraphenylporphyrin immobilized on a SA–CT polyelectrolyte complex and alginate solid gel is higher than that of FTPP immobilized on chitosan solid gel. Spectral-luminescent properties of polysaccharide–FTPP systems and the surface structure of carriers are studied via atomic force microscopy to determine the mechanism of the increase in porphyrin activity when it is fixed on alginate-containing carriers. It is suggested that aspects of the supramolecular structure of solid gels are responsible for the increase in the photocatalytic activity of FTPP upon immobilization on alginate-containing polysaccharide systems.

Solid-phase photosensitizing systems active in the generation of singlet oxygen (1O2) are obtained from fluorinated tetraphenylporphyrin (FTPP) immobilized on polysaccharide aerogels (chitosan and calcium alginate). Immobilization is carried out in a supercritical carbon dioxide (SC–CO2), or by planting FTPP on an aerogel (AEG) from a solution in chloroform. The kinetic parameters of the oxidation of tryptophan in an aqueous medium and anthracene in SC–CO2 are found using these photocatalytic systems. It is shown that the immobilization of porphyrin on a chitosan aerogel does not affect the effective rate constant of photooxidation. Active photocatalytic systems for FTPP immobilized on AG of calcium alginate are obtained only by impregnating the polymer with FTPP molecules in SC–CO2. It is found that FTPP immobilized on both chitosan and calcium alginate aerogels retains its functional activity for 3–4 cycles in model photooxidation processes. Differential thermal analysis is used to explain the differences between the photocatalytic activity of solid-phase aerogel systems containing porphyrin photosensitizers. Treatment with chloroform in particular has almost no effect on the thermooxidative destruction of the FTPP–chitosan aerogel system. A change in the thermooxidative destruction of the catalyst after treating the FTPP–AG system of calcium alginate with chloroform testifies to a change in structure of the system. It is concluded that photostable photosensitizing systems based on aerogels of calcium alginate or chitosan containing fluorinated tetraphenylporphyrins can be used for the photooxidation of organic substrates in both aqueous solutions and a supercritical medium.

IR spectroscopy is used to show that aerogels based on the interpolyelectrolyte complexes (IPEC) form in slightly acidic aqueous solutions at initial molar ratios ≥1.5 of aqueous solutions of chitosan and sodium alginate. Two to three times more hydroxylophine (in sc-CO2) can be introduced into AG-based matrices than into the corresponding polymer films of the same mass, due obviously to the larger surface area of the AG. It is found the preliminary solubilization of TAI with pluronic F-127 contributes to additional slowing of the release of the active substance from the matrices into a model biological environment.

В среде СК-CO получены композиции на основе хитозана и замещенных диарилимидазолов (ДАИ), обладающих противоопухолевым действием, с замедленным высвобождением активных веществ. Установлено, что использование воды (0,17 об. %) в качестве сорастворителя в процессе СКФ-импрегнации хитозана диарилимидазолами приводит к увеличению содержания ДАИ в полимерной матрице, очевидно, за счет увеличения степени набухания матрицы хитозана в среде СК-CO в присутствии воды. Интересно отметить, что влияние воды на скорость выхода СКФ-введенных диарилимидазолов из матрицы в модельную среду с рН 1,6 определяется структурой диарилимидазолов. Впервые показано, что солюбилизация молекул ДАИ плюроником F-127 перед их СК-введением в матрицу хитозана может использоваться как дополнительный эффективный способ пролонгирования действия матричных лекарственных композиций. Compositions based on chitosan and substituted diarylimidazoles (DAI), which have an antitumor effect, with a slow release of active substances have been obtained in the SC-CO medium. It has been established that the use of water (0.17 % by volume) as a co-solvent during SCF-impregnation of chitosan with diarylimidazoles leads to an increase in the content of DAI in the polymer matrices. Obviously, it is due to an increase in the degree of chitosan swelling in the SC-CO medium in the presence of water. It is interesting to note that the effect of water on the release rateof diarylimidazoles from the polymer matrices into the model medium with pH 1.6 was determined by the structure of diarylimidazoles. For the first time it has been shown that the solubilization of DAI molecules by Pluronic F-127 before their SC-introduction into the matrices of chitosan can be used as an additional effective method of prolonging the action of matrix preparations.

Методом флуоресцентной микроскопии изучено распределение фотоактивных соединений (ФАС) в полимерных матрицах, импрегнированных в среде сверхкритического диоксида углерода (СК-С0). Показано, что характер распределения ФАС в полимерах зависит от природы матрицы, степени взаимодействия вводимых молекул ФАС с фрагментами полимера, соответствующих коэффициентов диффузии. Такая информация может оказаться востребованной при разработках функционально ориентированных полимерных систем, импрегнированных ФАС (гетерогенный катализ, фотохромные материалы, медицина). Fluorescence microscopy was used to study the distribution of photoactive compounds (PAC) in polymer matrixes impregnated in supercritical carbon dioxide (SC-CO). It is shown that the character of the PAC distribution in polymers depends on the nature of the matrix, the degree of interaction of the introduced compounds with polymer fragments, and the sizes of the photoactive compounds corresponding diffusion coefficients. Such information may be in demand for the development of functionally oriented polymer systems impregnated with РАС (heterogeneous catalysis, photochromic materials, medicine).

The heterospin copper(II) complex, ((pyridin-2-ylmethylene)-4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl)-3,6-di- tert -butylcatecholatocopper(II) ( I ), is synthesized and characterized by IR spectroscopy, magnetochemistry, EPR, and X-ray diffraction analysis. The one-electron oxidation of complex I by AgBF 4 affords the biradical copper(I) complex: bis[((pyridin-2-ylmethylene)-4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl)]copper(I) ( II ). An analysis of the parameters of isotropic EPR spectra of complexes I and II indicates that they are biradicals with the fast ( I ) and intermediate ( II ) exchange interaction between the radical centers.

A series of heterospin bis-o-semiquinone cobalt, nickel, and copper complexes (4-TEMPO-oxy-3,6-di-tert-butyl-o-benzoquinone derivatives) is synthesized: (DMSO)Cu(4-TEMPO-O-3,6-DBSQ)2 (I), (THF)2Ni(4-TEMPO-O-3,6-DBSQ)2 (II), (Py)2Ni(4-TEMPO-O-3,6-DBSQ)2 (III), and (Py)2Ni(4-TEMPO-O-3,6-DBSQ)2 (IV) (4-TEMPO-O-3,6-DBQ is 4-(3,6-di-tert-butyl-1,2-dioxocyclohexa-3,5-dien-4-yloxy)-2,2,6,6-tetramethylpiperidine-1-oxyl 4-oxy-2,2',6,6'-tetramethylpiperidine-1-oxyl). All complexes are characterized by elemental analysis, IR spectroscopy, magnetochemistry, and EPR. The structure of complex I is determined by X-ray diffraction analysis (CIF file CCDC no. 1882878). The coordination polyhedron of the copper atom in the molecular structure of the Cu(II) bis-o-semiquinone complex with dimethyl sulfoxide (DMSO) is a distorted tetragonal pyramid, whose equatorial plane contains the o-semiquinone ligands, and the DMSO molecule occupies the apical position. The magnetic properties of complexes I–IV are consistent with their compositions and structures. The magnetic behavior of copper complex I and nickel complexes II and III is determined by the balance of two contributions: metal–ligand ferromagnetic exchange interaction and ligand–ligand antiferromagnetic interaction. The temperature dependence of the magnetic moment of cobalt complex IV shows the redox isomeric transformation conjugated with the spin transition, which is characteristic of complexes of this type. No participation of nitroxyl radical centers is observed in intermolecular coordination.

Abstract—Sustained-release compositions based on chitosan and substituted diaryl imidazoles (DAIs) possessing antitumor activity were obtained in supercritical carbon dioxide (SC–CO2). It has been found that the use of water (0.17 vol %) as a co-solvent during SCF impregnation of chitosan with DAIs leads to an increase in the DAI content in the polymer matrix. Obviously, this is due to an increase in the degree of chitosan swelling in the SC–CO2 medium in the presence of water. It is interesting to note that the effect of water on the rate of release of the SCF-introduced DAIs from the matrix into a model medium with pH 1.6 is determined by the DAI structure. For the first time, it is shown that the solubilization of DAI molecules by Pluronic F-127 before their SCF introduction into the chitosan matrix can be used as an additional efficient way to prolong the action of matrix medicinal compositions.

The distribution of photoactive compounds (PACs) in polymer matrices impregnated in supercritical carbon dioxide (SC-CO2) was studied by fluorescence microscopy. The pattern of PAC distribution in polymers was shown to depend on the nature of the matrix, the degree of interaction between introduced PAC molecules and polymer fragments, and corresponding diffusion coefficients. Such information may be in demand for the design of functionally oriented polymer systems impregnated with PACs (heterogeneous catalysis, photochromic materials, and medicine).

The immobilization of fluorinated tetraphenylporphyrins (FTPPs) into tetrafluoroethylene copolymers (fluoroplast F-42 and MF-4SK, a perfluorinated sulfonic acid cation exchanger in H + -form) is conducted in supercritical CO 2 (scCO 2 ). The effects the conditions of immobilization (the temperature and pressure of scCO 2 , reaction time, and the addition of cosolvents) and the structure of the carrier polymer have on the content of porphyrin in these polymers is studied. The porphyrin-loaded polymer systems are shown to exhibit photosensitizing activity in anthracene and cholesterol oxidation in scCO 2 . Under conditions of photocatalysis, chemical and functional stability is a feature of only MF-4SK polymer systems; this is attributed to the formation of protonated forms of the porphyrins and their interaction with SO 3 − -groups of the polymer (an ion exchange process), which prevents leaching of the FTPP from the polymer matrix. The photocatalytic process actually occurs inside the matrix of the perfluorinated copolymer, with the protonated form of the porphyrin acting as a photosensitizer. The rate constant of anthracene photooxidation in the presence of FTPP-loaded MF-4SK films in scCO 2 is found to pass through a maximum as a function of the porphyrin content and the polymer film thickness. The use of such catalytic systems for cholesterol photooxidation in scCO 2 is shown to produce a virtual monoproduct (yield, ~10%): 6-formyl-B-norcholestane-3,5-diol, a compound with high biological activity.

Formation of long-lived coloured forms of indoline spirocompounds (spirooxazines and spiropyrans) molecules under matrix immobilization in polar polymer of different chemical structure using supercritical fluid impregnation is studied. Some of such systems acquire additional optical characteristics besides colour – they become fluorophores. Mechanisms of observed changes in optical properties and long-term stability of the resulting coloured forms of indoline spirooxazine in polymers are discussed. Electronic absorption spectra of such coloured forms were recorded in supercritical carbon dioxide medium as well as on air. The results can be applied for creation of optical, biomedical and electronic devices and stable fluorescence composite coverings.

The polylactide acrylate derivatives have been synthesized via the esterification of terminal hydroxy and carboxy groups of polylactide with acrylic acid chloroanhydride and ethylene glycol monoacryl ester. Spatially cross-linked structures suitable for the formation of implants have been prepared by the photopolymerization of these derivatives.