The article is devoted to the study of processes of ion-exchange sorption of zinc ions in a dense moving ion exchanger bed apparatus. A mathematical description of the ion exchange process is proposed, taking into account the following simplifying assumptions: the process equilibrium is described by the Nikolskogo adsorption isotherm equation; the rate of ion exchange is limited internal diffusion; the structure of the movement of the solution and the ion exchanger in the apparatus is described by the ideal displacement model. In accordance with the accepted assumptions, a mathematical description of the process is formulated, including the material balance equations forAa solution, the equation of the adsorption isotherm, the equation of diffusion kinetics, as well as the initial and boundary conditions. The solution of the problem is carried a piecewiseiteration method. To test the adequacy of the developed model to the real process, experimental studies of processes of ion-exchange sorption of heavy metal ions on the & Kcy;& Ucy;-2-8 sulfonic acid cation exchanger in a laboratory dense moving ion exchanger bed apparatus. The concentration of the initial solution increased linearly. During the research, curves of changes in solution concentration along the height of the apparatus and output ion exchange curves were taken. Comparison of the results of calculation and experiment made it possible to conclude that the developed mathematical description is adequate to the real process. The discrepancy between the calculation and the experiment does not exceed 12%. Recommendations are given on the application of the obtained dependences for practical application.

Relevance. The development of antimicrobial drugs and alternative methods, technologies and means of prevention, diagnosis and treatment of human infectious diseases caused by antibiotic-resistant microorganisms is one of the priorities of ensuring the biological safety of the country. Aims. To evaluate the bactericidal activity of tetrapyrrole macroheterocycles (porphyrins) at different light irradiation durations in relation to staphylococci, in vitro. Materials and methods. Studied strains of microorganisms: museum strains of microorganisms – S. aureus ATCC 29213, S. epidermidis ATCC 14990 and antibiotic-resistant strains of bacteria of the genus Staphylococcus (n=18) isolated from clinical biomaterial and from environmental objects in a medical organization. The studied chemical compounds are three different compounds of water-soluble asymmetrically substituted porphyrins containing heterocyclic fragments on the periphery of the porphyrin cycle (residues of benzoxazole, N-methylbenzimidazole and benzothiazole). Results. The activity of all three porphyrin compounds in relation to museum strains of staphylococcus and 77.8% of clinical antibiotic-resistant strains (n=14; 95% CI 20.1-97.5) turned out to be maximal (complete lysis) after 10 minutes of irradiation. Conclusions. The tested tetrapyrrole macroheterocycles (porphyrins) exhibit bactericidal activity against museum and clinical strains of staphylococcus, with different levels of antibiotic resistance, which determines Keywords: antibiotic resistance, water-soluble porphyrin, photodynamic inactivation, photosensitizer, photochemistry, staphylococci No conflict of interest to declare.

The paper presents the results of theoretical and experimental studies of new mesogenic molecular complexes based on 4-alkylsulfonic acids and 4-pyridyl-4'-n-alkyloxybenzoates. Using quantum chemistry methods (DFT), the structural units of the systems under study, which are hydrogen-bonded complexes, were modeled. The relationship between molecular parameters, electronic effects of substituents, gas-phase acidity and characteristics of the formed H-complexes is shown. Electron-donating alkyl substituents in the para-position of benzenesulfonic acid reduce gas-phase acidity compared to the unsubstituted molecule, enhancing the electron-withdrawing properties of the sulfo group. The type and potential barrier of the calculated potential functions of proton transfer from the sulfo group to the pyridine fragment in the molecular complexes under study allowed us to conclude that gas-phase acidity directly determines the characteristics of this process. It was found that para-alkyl-substituted benzenesulfonic acids form stronger hydrogen bonds in proton transfer complexes compared to unsubstituted benzenesulfonic acid. The synthesis of three samples of molecular complexes of 1:1 composition was performed (4-methylbenzenesulfonic acid : 4-pyridyl-4'-n-dodecyloxybenzoate, 4-ethylbenzenesulfonic acid : 4-pyridyl-4'-n-heptyloxybenzoate, 4-ethylbenzenesulfonic acid : 4-pyridyl-4'-n-dodecyloxybenzoate). IR spectra recorded at room temperature showed that the systems under study are H-complexes with proton transfer from the sulfo group to the pyridine fragment with an intermolecular hydrogen bond of the N -H center dot center dot center dot O type. It was determined that all H-complexes have enantiotropic mesophorism, as evidenced by DSC and polarization thermomicroscopy data. The recorded mosaic textures in a polarizing microscope suggested that the samples under study had a smectic type of mesophase. It has been shown that the temperatures of phase transitions from the mesophase to the isotropic liquid phase depend on the length of the alkyl substituents in the components of the complexes, which may be a manifestation of the odd-even effect.

Microcapsules with gelatin shells are obtained by coacervation. In the process of microcapsulation, the shells of microcapsules are treated with ozone and ozonated water is introduced into their core. Magnetic sensitivity was imparted to microcapsules by introducing magnetite in their shell. The influence of the composition and concentration of microcapsules in an aqueous emulsion on the durability of the tool during blade cutting is studied. It is shown that the lubricating and cooling technological means obtained by introducing ozonated water into the core of a gelatin microcapsule is more effective for increasing the tool’s durability during blade cutting.

Palladium-catalyzed heterylation of monobromophenyl-substituted zinc(II) porphyrin with small heterocycles (benzothiazole, benzoxazole, and N-methylbenzimidazole) was carried out. As a result, unsymmetrical heterylphenyl-substituted zinc(II) porphyrins soluble in organic solvents were obtained. The interaction of heteryl-substituted zinc(II) porphyrins with alpha-helical proteins was studied by spectral methods using bovine serum albumin in aqueous organic solvents. It was found that the titration of the zinc(II) porphyrins with albumin in a sodium phosphate buffer involves a number of equilibria including complexation and aggregation. In the case of porphyrins containing N-methylbenzimidazole and benzoxazole residues, self-aggregation processes initiated by absorption of organic solvent molecules by the protein predominate. It was found that more hydrophobic nature of zinc(II) porphyrin with benzothiazole residue promotes the complex formation with the protein. The photochemical properties of zinc(II) porphyrin with a benzothiazole residue, capacity for the photooxidation of the alpha-helical protein, and the high affinity of protein to this porphyrin make it a promising candidate for the potential applicability for photodynamic inactivation.

Directed synthesis of a new cationic monoheteryl-substituted porphyrin, 5-[4′-(1′′,3′′,7′′-trimethyixanth-2′′-yl]-10,15,20-tris-( N -methylpyridinium-3′-yl) porphyrin triiodide was carried out. This porphyrin is in a partially associated state in Tris-buffer solutions at pH = 7.4, and has a long fluorescence lifetime (~9 ns). It has been found that the synthetic nucleic acid binds the synthesized porphyrin in the groove with an affinity constant of 2.3×10 7 . It has been shown that the porphyrin binding by poly[d(AT) 2 ] leads to a decrease in the particle size. Photoirradiation of the porphyrin complex with poly[d(AT) 2 ] by visible light leads to the destruction of the nucleic acid and enhances the porphyrin photolysis.

Glycosylated substituted derivatives of 5,10,15,20-tetraphenylporphyrin, namely 5-(4′-O-galactosylphenyl)-10,15,20-tris(N-methylpyridin-3-yl)porphine, 5,15-bis(4′-O-galactosylphenyl)-10,20-bis(N-methylpyridin-3-yl)porphine, 5,10,15,20-tetra(N-methylpyridin-3-yl)porphin, and 5,10,15,20-tetra(4-O-galactosylphenyl)porphin, were synthesized and their basic properties in acetonitrile at 298 K were studied by spectrophotometric method.

Microcapsules consisting of only a gelatin shell, a gelatin shell with magnetite, and a gelatin shell filled with ozonated water (ozonated water in the microcapsule core was adsorbed by activated carbon), a gelatin shell treated with ozone, a gelatin shell with ozone-treated magnetite, and a gelatin shell containing magnetite and ozonated water were obtained by simple coacervation method. The effectiveness of using aqueous emulsions of the shells as production lubricants and coolants during cutting in turning operations on a 16K20 screw-cutting lathe using side cutters made of high-speed R6M5 steel was investigated. The set of processed materials included 12Kh18N10Т stainless steel, 40Kh chromium steel, and VT5-1 and VT-6 titanium alloys. The introduction of ozone into the composition of microcapsules is shown to increase the period of normal wear of the cutting tool. In addition, the duration of the initial wear-out period increases. It was revealed that the wear resistance of cutting tools increased most strongly if microcapsules with gelatin shells filled with magnetite and ozonated water are used. The increase in the wear resistance of a cutting tool can be explained by the formation of lubricant films at the interface between the tool and the material being processed; the films may include metal polymers and complex compounds of atomic iron, covering surface irregularities that are sterically inaccessible to metal polymers. Based on this hypothesis, an approach has been proposed, which enables predicting the potential effectiveness of production lubricants and coolants using quantum chemistry methods.

The formation of bimetallic composites by the electrochemical codeposition of Fe(III)Cl-5,10,15,20-tetrakis(4-aminophenyl)porphyrin and Mn(III)Cl-5,10,15,20-tetrakis(4-aminophenyl)porphyrin was studied. The composites were obtained by the superoxide-assisted electrochemical deposition from mixed solutions of DMSO with equal concentrations of porphyrins. The spectral analysis of the composites showed that they were enriched in the Mn complexes of porphyrin. A comparative analysis of the morphology, electroactive surface area, and specific features of oxygen electroreduction on the films of individual porphyrins and the composites was carried out. It was shown that the catalytic activity of bimetallic composite was higher than that of the materials based on the individual metal complexes.

The effect of amino acid fragments in tetraphenylporphin derivatives on the pH range of porphyrin dication dominance was studied. For this purpose, the protonation processes of unsymmetrically substituted derivatives of 5,10,15,20-tetraphenylporphyrin: 5-(4′-aminophenyl)-10,15,20-triphenylporphine, 5-(4′-tyrosinylamidophenyl)-10,15,20-triphenylporphine, and 5-(4′-glycinacylaminophenyl)-10,15,20-triphenylporphine in acetonitrile were considered. It was found that in acidic acetonitrile solutions the pH range of dominating the doubly protonated form depends on the nature of the substituent in the para-position of the phenyl fragment on the periphery of the porphyrin ring: electron-donor substituents expand the pH range of dominating the porphyrin dication, whereas electron-acceptor substituents decrease it. The calculation of the energies of the molecular orbitals of the studied compounds by the DFT method with the B3LYP/cc-pVDZ set showed good agreement between the experiment and the calculations.

Transition-metal catalyzed cyanation by Rosenmund-von Braun is conventional approach to substituted phthalonitriles. However, low reaction yields, rough reaction conditions and limited access to halogenated compounds make this technique unreliable in many cases. In this work, we have established the direct C-H functionalization of 5,6-bis(4-bromophenyl)pyrazine-2,3-dicar-bonitrile(4) with benzothiazole affording the corresponding 5,6-bis(4-(benzo[d]thiazol-2-yl)phe-nyl)pyrazine-2,3-dicarbonitrile(5). The reaction pathway starts from the 4-bromoaniline, which was subjected to react with formaldoxime under Meerwein reaction conditions to give the oxime of 4-bromobenzaldehyde. Subsequent hydrolysis of oxime leads to formation of 4-bromobenzaldde-hyde. To prepare 1,2-bis(4-bromophenyl)-2-hydroxyethanone, benzoin aldehyde condensation was employed using NaCN as a catalyst. The precipitate obtained then was oxidized with CuSO4 to afford 1,2-bis(4-bromophenyl)ethane-1,2-dione. Condensation of diaminomaleodinitrile with 1,2-bis(4-bromophenyl)ethane-1,2-dione in glacial acetic acid led to the formation of 5,6-bis(4-bromo-phenyl)pyrazine-2,3-dicarbonitrile with 83% yield. Direct C-H functionalization was performed us-ing Pd/Cu-catalytic system in boiling toluene for 6 h in the presence of K2CO3 as a base and PPh3 as a ligand to obtain 5 in 73% yield. Structure of 5 was determined by Uv/Vis spectroscopy, mass spectrometry (MALDI-TOF), 1H and 13C NMR spectroscopy. According to B3LYP/cc-pVTZ cal-culations 5 has the structure of C2 symmetry. Assignment of vibrational modes of 5 was carried out via potential energy distribution analysis among internal coordinates. The complicated com-position of vibrational modes was noted. The simulated and experimental IR-spectra were satis-factorily agreed.

The effect of amino acid fragments on the spectral and complexing (with Zn2+ and Si2+) properties of asymmetrically substituted derivatives of 5,10,15,20-tetraphenylporphyrin: 5-(4'-amino-phenyl)-10,15,20-triphenylporphine, 5-(4'-tyrosinyl-amidophenyl)-10,15,20-triphenylporphine, 5-(4'- N-tretbutoxicarbonylthyrosinyl-amidophenyl)-10,15,20-triphenylporphine, 5-(4'-glycinacylamino-phenyl)-10,15,20-triphenyl-porphine, 5-(4'-N-tretbutoxy-carbonylglycine-aminophenyl)-10,15,20-triphenylporphine in acetic acid at 291-308K was studied. The kinetic parameters of the reactions of the formation of their zinc and copper complexes were determined. The effect of the chemical functionalization of the tetraphenylporphyrin molecule due to the addition of one or more biomolecules to the periphery of the macrocycle on the change in the spectral and coordination properties of the synthesized macromolecule is considered. It is shown that when identifying the patterns of "structure-activity", the most effective method for studying functionalized ligands is the spectrophotometric method, with which it is possible to qualitatively and quantitatively characterize the processes of acid-base equilibrium, complexation, and the influence of the nature of the solvent. It is shown that the change in the rate constants of the zinc acetate and copper acetate coordination reactions of the studied ligands depends on their stability in the reaction medium. It was found that in acetic acid, the tendency of the peripheral substituent to influence the complexing ability of ligands in relation to copper and zinc remained almost the same for all studied ligands. The interrelation of ligand complexation constants with electronic substitution effects, in particular with the total value of the Gammet constant of peripheral substituents, including both resonant and inductive components, the ratio of which depended on the molecular structure of peripheral substituents, is considered. It is shown that the complexation constants of the ligands studied formed a correlation with the total inductive Gammet constant sigma I of the substituent in the para-position of the phenyl ring, and the electronic effect of the substituent was determined mainly by inductive interactions.

An experimental and theoretical study of the structure and mesomorphic proper-ties of supermolecules (H-complexes) formed by 4-n-propyloxycinnamic acid (A) with 4,4'-azopyridine and 4,4'-dithiopyridine (B) has been carried out. The relationship between mesomorphic properties and structural features of H -com-plexes was shown. Using quantum chemistry (DFT) and FTIR spectroscopy methods, it was shown that as a result of self-organization in systems with a molar ratio of components 2:1 (acid : pyridine derivative), H-complexes of the compo-sition A center dot center dot center dot B center dot center dot center dot A are formed. The geometric shape of the H-complexes is deter-mined by the shape of the central molecules - 4,4'-azopyridine and 4,4'-dithio-pyridine. Molecular complexes with 4,4'-azopyridine have a rod-like structure, replacing the central azo group of the non-mesogenic H-complex component with a dithio group leads to a change in the H-complex geometric shape to an angular (V-shaped) one. The energies of H-complex formation and the characteristics of the formed intermolecular hydrogen bonds have been calculated. The geometric anisotropy of the H-complexes is estimated. With the help of experimental meth-ods (differential scanning calorimetry and polarizing optical microscopy), the presence of mesomorphic properties of the H-complex based on 4,4'-azopyridine and their absence in the H-complex based on 4,4'-dithiopyridine was shown. Using experimental and theoretical methods, it has been shown that the strength of the formed N center dot center dot center dot O-H hydrogen bonds in both complexes is comparable. Thus, the replacement of the -N=N- bridging group by -S-S- of the non-mesogenic component of the H-complex affects not only its geometry, but also the liquid -crystal properties.

ect of substituents on the spectral, coordination, and fluorescent properties of acetonitrile solutions of asymmetrically substituted tetraphenylporphyrins, namely 5-(4-aminophenyl)-10,15,20-triphenylporphine, 5-[4-(glycylamino)phenyl]-10,15,20-triphenylporphin, and 5-[4-(N-tert-butoxycarbonylglycylamino)phenyl]-10,15,20-triphenylporphin, was studied. The kinetic parameters of formation of their zinc complexes were determined. The rate constants of reactions of zinc acetate coordination with the studied ligands depend on their stability in the reaction medium. The doubly protonated forms of ligands had higher quantum yields than the monoprotonated forms, which is probably due to the redistribution of electron density in tetrapyrrole macrocycles controlled by inductive effects.

С помощью методов ДСК и поляризационной термомикроскопии определены температуры фазовых переходов и получены данные о мезоморфных свойствах трех анизотропных производных 1,2,5-тиадиазола: 4,7-бис(додецилсульфанил) [2,3,1]бензотиадиазол BTDA, 4,7-бис(додецилсульфанил)[1,2,5]тиадиазоло [3,4-c]пиридин PyTDA, 4,7-бис(додецилсульфанил)[1,2,5]тиадиазоло[3,4-c]пиридазин PrdTDA. Показано, что среди исследуемых соединений мезогенным является PrdTDA, для которого наблюдается индуцирование мезофазы в темепературном интервале 95.63 – 91.62 ºС в режиме охлаждения из изотропножидкой фазы. С помощью методов квантовой химии: DFT (B3LYP, B97D) с базисными наборами cc-pVTZ и 6-311++G** изучено строение и определены конформационные свойства свободной молекулы PrdTDA, а также смоделированы возможные межмолекулярные взаимодействия, наблюдаемые в кристаллической фазе. Анализ потенциальных функций внутреннего вращения алкилсульфанильных заместителей относительно циклического ядра показал, что молекула PrdTDA имеет 3 конформера. На основании структуры наиболее энергетически выгодного конформера молекулы выполнена геометрическая оптимизация димерного фрагмента цепочечного ассоциата PrdTDA∙∙∙PrdTDA, характерного для кристаллической фазы. Анализ распределения электронной плотности (NBO) показал, что межмолекулярное взаимодействие возможно за счет неподеленных пар LP(S), LP(N) и разрыхляющих NBO σ-типа σ*(С–N), σ*(S–N). Показана прямая связь между строением молекул и возможностью индуцировать мезофазу за счет нековалентных межмолекулярных взаимодействий – халькогенной связи.

Basic properties of 5,10,15,20-tetraaryl-21-thia- and 5,10,15,20-tetraaryl-21,23-dithiaporphyrins in acetonitrile were examined spectrophotometrically. The geometry of the heteroporphyrins was optimized in the DFT approximation (hybrid functional B3LYP/6-311G). The relationship between the geometric structure and the basic and spectral properties of the porphyrins was investigated. The ability of the double-protonated forms of thia-substituted heteroporphyrins to coordinate perchlorate and trifluoroacetate ions in neutral solvents, which can be useful for creation of liquid-phase sensor materials, was discovered for the first time.

By differential scanning calorimetry and polarized light thermal microscopy the phase transition temperatures are determined and the data on the mesomorphic properties are obtained for three anisotropic 1,2,5-thiadiazole derivatives: 4,7-bis(dodecylsulfanyl)[2,3,1]benzothiadiazole BTDA, 4,7-bis (dodecylsulfanyl)[1,2,5]thiadiazolo[3,4-c]pyridine PyTDA, 4,7-bis(dodecylsulfanyl)[1,2,5]thiadiazolo[3,4-c]pyridazine PrdTDA. It is shown that among the studied compounds only PrdTDA is mesogenic. The induction of the PrdTDA mesophase is observed in a temperature range of 95.63-91.62 °C on cooling from the isotropic liquid phase. Using the quantum chemistry method DFT (B3LYP, B97D) with the cc-pVTZ and 6-311++G** basis sets, the structure of a free PrdTDA molecule is studied, its conformational properties are determined, and possible intermolecular interactions occurring in the crystalline phase are simulated. The analysis of potential functions of internal rotation of alkylsulfanyl substituents relative to the cyclic core shows that the PrdTDA molecule has three conformers. Based on the structure of the most energetically favorable conformer of the molecule, the geometry of the dimeric moiety of PrdTDA···PrdTDA chain associate characteristic of the crystalline phase is optimized. The analysis of electron density distribution (NBO) suggests that intermolecular interaction is possible due to LP(S), LP(N) lone pairs and σ-type anti-bonding NBOs σ*(C–N), σ*(S–N). A direct relationship between the molecular structure and the possibility of inducing mesophase due to non-covalent intermolecular interactions–chalcogen bond–is shown.

Water-soluble asymmetrically substituted porphyrins containing the heterocyclic fragments (benzoxazole, N -methylbenzimidazole, and benzothiazole residues) at the periphery of the porphyrin ring were synthesized using the C-H-activation method. The compounds were identified by electron absorption spectroscopy, 1 H NMR spectroscopy, and mass spectrometry. The quantum yields of singlet oxygen generation and complexation ability of the synthesized porphyrins with respect to albumin were determined. The affinity of albumin to the porphyrins with the N -methylbenzimidazole and benzoxazole residues was shown to be nearly two times higher than the affinity to the porphyrin with the benzothiazole fragment. The synthesized porphyrins can efficiently interact with proteins. The bactericidal activity of the synthesized porphyrins to archival strains of microorganisms was studied. The lytic activity for gram-positive Staphylococcus spp. bacteria under photoirradiation conditions was revealed.

Using theoretical conclusions from the Gouterman four-orbital model, a detailed analysis of the formation of absorption and fluorescence spectra of free bases and their zinc complexes has been performed for 5,10,15,20-tetraphenyl-21-oxaporphyrin and 5,10,15,20-tetraphenyl-21,22-dioxaporphyrin. The influence of the symmetry of the molecule on the position and shape of the bands in the electronic absorption and fluorescence spectra is shown. The kinetic parameters of the reactions of complexation of oxasubstituted derivatives of 5,10,15,20-tetraphenylporphine with d-metal salts (Cu(II), Zn(II), and Co(II)) at 288–308 K have been determined for the first time. The kinetic data obtained for oxasubstituted derivatives have been compared with results obtained for their classical analogue, tetraphenylporphine.