Preview

Fine Chemical Technologies

Advanced search
Vol 14, No 3 (2019)
View or download the full issue PDF (Russian)
5-32 3413
Abstract

The problem of activity coefficients dependence of indium(In)-containing complex species and of corresponding concentration formation constants from qualitative and quantitative composition of aqueous solutions is discussed. The Bmnsted-Guggenheim-Scatchard’s model (Specific ion Interaction Theory, SIT), basing on extended semi-empirical Debye-Huckel equation in third approximation is supplied. The checking of data for formation constants of complexes on comparability and consistency, including for different background electrolytes can be done using this model. The survey of basic specific interaction coefficients (SIC) is done. The constancy of this coefficients is permissible in the definite ionic strengths ranges, or it’s necessary using two-parameters coefficients fitting. The classical SIT model is modified by the introduction of mixing parameters (SIC of same charge ion). On the basis of the numerical critical analysis of the available literature experimental data, with employment of the SIT, thermodynamic formation (stability) constants of chloro-, sulfato-aqua-complexes and hydrolysis constants of indiumfII) and related specific interaction coefficients (“non-ideality” parameters) in acidic aqueous solutions (pH < 5.5) at ambient temperature (20-25 °C) are calculated. The quotients of cationic and anionic complexes parts in SIC are separated according to empiric Ciavatta’s approach. Discrepancies of published «thermodynamic» constants may be caused by evidencing methodological and calculated errors (essential change of activity factors in series of experiments or various competing ion equilibria are neglected), as well as inaccuracies of extrapolation methods and choice of conditional standard state or erroneous evaluation of formal and standard potentials, but with the exception of alternative Baes-Mesmer’s nonlinear regression procedure. The job’s results could be used for modeling of the indium(III) state in some aqueous solutions and for study of indium and other metal ions complexation or prediction of their electrochemical and geochemical behaviour.

CHEMISTRY AND TECHNOLOGY OF MEDICINAL COMPOUNDS AND BIOLOGICALLY ACTIVE SUBSTANCES

33-41 293
Abstract

Triterpenoids from birch bark are valuable biologically active substances. They exhibit important biological properties. However, triterpenoids are insoluble in water due to their hydrophobicity. In order to increase their bioavailability we developed a technique for obtaining spherical amorphous nanoparticles (SANP) by their precipitation with water from a solution in THF. In the form of nanoparticles, triterpenoids show additional useful properties: they can be loaded with hydrophobic substances. SANP were also shown to be effective immunological adjuvants. This article is devoted to the study of conditions that could optimize their production. As a result, it was shown that among the three investigated solvents miscible with water - acetone, dioxane, THF -the latter gives the best results. Lowering temperature decreases the size of SANP. An increased temperature leads to the formation of betulin crystals. When the concentration of triterpenoids in THF is higher than 5 mg/ml, crystals of betulin also begin to form. The results of this study lead to the assumption that the main parameter of the process determining the formation of SANP is the rate of the solvent diffusion into water.

42-49 190
Abstract

Research methods based on the use of RNA interference mechanisms are now included among the basic methods of molecular biology. Drugs based on siRNA are being developed for the treatment of cancer, infectious diseases and other pathologies that are associated with impaired Junctions of specific genes. One of the main problems of siRNA-based drug development is their efficient and safe delivery to target cells. Modern delivery strategies are based on the use of chemical compounds or biological carriers, such as viruses. Lipid nanoparticles (liposomal agents) are the most advanced platform among non-viral vectors for the delivery of gene materials into cells. In this paper, a scheme has been proposed and the synthesis of new cationic amphiphiles has been carried out as the basis for the means of delivering siRNA to target cells. Synthesized amphiphiles belong to two types of cationic lipids: with a permanently charged amino group in the form of a salt and with an ionizable polar block. Ionized amphiphiles are a new generation of cationic lipids that exhibit reduced toxicity and immunogenicity. They undergo ionization only in the acidic environment of endosomes during intracellular transport in the cytosol, which leads to the release of the encapsulated cargo. The structure of the target compounds is based on diethanolamine derivatives, which is a spacer between the hydrophobic block and the polar fragment. The hydrophobic block contains palmitoyl residues, and the polar one - ethylenediamine and 3-diethylaminopropylamine derivatives. The developed synthetic scheme is distinguished by the simplicity and versatility of the proposed approach, which allows it to be used in the preparation of a series of samples in preparative quantities necessary for the subsequent physicochemical and biochemical studies.

50-59 257
Abstract

The possibility of applying silver, cadmium and zinc sulfide nanoparticles (npAg2S, npCdS and npZnS) obtained using Shewanella oneidensis MR-1 and Bacillus subtilis 168 bacterial cultures for the creation of a new class of polymeric bionanocomposite materials was investigated. Biogenic nanoparticles obtained in aqueous solutions of the corresponding salts in the presence of various types of microorganisms are characterized by the presence of protein molecules on their surface. The molecules composition is determined by the bacterial culture. Proteins stabilize them and allow the nanoparticles to covalently join the active groups of polymeric carriers. Aminated chloromethylated polystyrene microspheres, as well as ion-exchange resins of various types, were used as polymeric matrices. Analysis of interaction with them can be used as a method for studying the properties of biogenic nanoparticles of metal sulfides for subsequent successful selection of a polymeric carrier. The immobilization of biogenic nanoparticles of metal sulfides onto the surface of aminated chloromethylated polystyrene microspheres was found to depend on the level of stability of aqueous nanoparticle suspensions and is determined by the negative charge of biogenic npAg2S, npCdS and npZnS, which suggests covalent binding and the electrostatic interaction of the components in the composition of the polymer bionanocomposite. A comparative analysis of the parameters of nanoparticles depending on the strain used in the biosynthesis was carried out. Analysis of the main physicochemical characteristics of npCdS and npZnS showed that the small size of nanoparticles (npCdS - 5 nm, npZnS - up to 2 nm) and the presence of luminescence peaks at wavelengths less than 400 nm classify them in the blue region of the fluorescence spectrum and identify them as quantum dots. Thus, the possibility of introducing fluorescent quantum dots of nanoparticles of metal sulfides of biogenic origin into various polymeric matrices has been demonstrated, which contributes to the expansion of the horizons for using a new class of nanoparticles to create polymeric bionanocomposites.

60-69 163
Abstract

The article proposes an approach for obtaining the derivatives of hetarylmethylthioaryloxyalcane PPARS/fi agonists containing sulfoxide and sulfone fragments in the linker, the parent compound for the synthesis being GSK-516 - (2-methyl-4-[4-methyl-2-(4-trifiuoromethylph.enyl)-th.iazole-5-ylmethylsulfanyl]phenoxy)acetic acid obtained as a result of sequential S- and O-alkylation of mercaptocresol by thiazolyl methyl chloride and ethyl bromacetate at key stages. Derivatives of GSK-516, as well as sulfoxide and sulfone were synthesized for the first time by oxidating acyclic sulfur with meta-chloroperbenzoic acid. The structures of the synthesized compounds were confirmed by HPLC-MS, elemental analysis and JH, 13C NMR. The spectral characteristics of target compounds were compared by NMR. When passing from sulfide to sulfoxide and further to sulfone, it was found that the shift of the methylene group connecting the thiazole ring with the sulfur atom is moved to the weaker field. The antithrombotic activity of the obtained compounds was investigated by measuring platelet aggregation in platelet-rich plasma by the Bourne turbidimetric method. It was stated that sulfonic derivative GSK-516 has the highest antithrombotic activity.

SYNTHESIS AND PROCESSING OF POLYMERS AND POLYMERIC COMPOSITES

70-77 168
Abstract

The effect of temperature and external electric field on the adhesion characteristics in the polychloroprene-schungite system was investigated. It is shown that an increase in temperature and orientation of macromolecules of polychloroprene in an external electric field significantly increase the bond strength between the studied components. The detected effects are explained from the viewpoint of the possibility of direct chemical interaction ofshungite with polychloroprene macromolecules oriented in a certain way in the region of an adhesive compound formation. This is facilitated by the structural features of schungite (the presence of paramagnetic centers, fullerene-like structures, metal oxides) and polychloroprene in shungite, as well as by the creation of the most optimal modes for implementing this interaction. To assess the strength of the interaction between polychloroprene and the surface of shungite we used a method for determining the stress of exfoliation of a polymer film from the surface of a shungite plate. It was established that the greatest effect in strengthening the bond between polychloroprene and the surface of shungite is achieved when a polymer film is formed from a solution in carbon tetrachloride on a negative electrode (cathode). The strength of the bond between shungite and the polychloroprene film formed on the cathode is more than two times higher than this parameter when forming the same film on the anode. The energy expended during the peeling of a film formed on the cathode is twice the energy of exfoliation from the shungite plate of the film formed on the anode. The analysis of the change in the supramolecular structure of polychloroprene in the polychloroprene-shungite system as a result of the orientational influence of an external electrostatic field was carried out using the temperature dependence of the tangent of the dielectric loss angle of the systems under study. It is shown that a polychloroprene film formed in an electrostatic field has a more ordered structure compared to a similar sample formed without a field. This fact is evidenced by the shift of the maxima toward higher temperatures in the relaxation spectra of the dipole polarization for the system formed without the field, and the system formed on the cathode. The polychloroprene film containing finely dispersed shungite as a filler and formed on the cathode is characterized by an increased value of the tangent of dielectric loss angle and an increased number of peaks of dipole relaxation in the temperature range studied.

CHEMISTRY AND TECHNOLOGY OF INORGANIC MATERIALS

78-89 188
Abstract

Ceramic samples of the (1-2x)BiScO3-xPbTiO3-xPbMg1/3Nb2/3O3 system in the whole compositions region x = 0-0.50 were synthesized. According to the X-ray diffraction studies (XRD), the region of solid solutions with perovskite structure formation in the system was determined (x = 0.23-0.50). The presence of a morphotropic phase boundary between tetragonal and rhombohedral forms of solid solutions was established at x = 0.40-0.42. Refined XRD with profile peak analysis established the presence of the additional cubic phase with broadened X-ray reflexes in the solid solutions along with the main phase. It was concluded that the main and additional phases are located in the volume and in the surface layer of ceramic crystallites, respectively. The crystal structures of phases in the polarized and depolarized sample with x = 0.42 were determined by the Rietveld method. It was found that the monoclinic perovskite phase is present in the polarized sample. Temperature-frequency dependences of dielectric permittivity and losses of solid solutions were studied. It was found that the increasing content of BiScO3 in samples causes a change in their dielectric properties from the usual ferroelectric (FE) in the region (1-2x) = 0-0.08 to ferroelectric-relaxor (FE-R) in the region (1-2x) = 0.08-0.40, and then to the properties of dipole glass with weak correlations in the region (1-2x) > 0.40. It was found that the samples with x = 0.434 and 0.446 below Tc = 414 and 445 K spontaneously pass to the FE state. In the samples with x = 0.42 the application of an electric field of 2.0 kV/ cm induces a transition from FE-R to FE state with Tc = 350 K, which remains after the field is removed.

ANALYTICAL METHODS IN CHEMISTRY AND CHEMICAL TECHNOLOGY

90-97 229
Abstract

The chemiluminescent reaction of luminol is widely used for analytical purposes. Surface-active components of biological membranes are often present in biochemical studies and in many real objects of analysis. Their influence on the chemiluminescent reaction of luminol has not been systematically studied. Therefore, it is necessary to investigate this chemiluminescent reaction in organized molecular systems - micellar, vesicular and other systems simulating biological membranes. Micellar medium may also provide an additional opportunity to control chemiluminescent reactions, primarily with the aim of increasing their efficiency. The kinetics of the chemiluminescent oxidation of luminol and its hydrophobic analogue N-octylluminol with a hypochlorite ion in aqueous solutions and micellar solutions of non-ionic surfactant Triton X-100 was studied in the present work. It was shown that the growth and fading of the luminol and N-octylluminol chemiluminescence is adequately described by a two-exponential dependence, and the effective rate of increase in the intensity of chemiluminescence is directly proportional to the concentration of the hypochlorite ion. The dependences of the rate of accumulation and consumption of the intermediate product on the presence and concentration of surfactants in the reaction mixture are determined. The results are discussed in terms of the effect of localization of the reagents and intermediate reaction products.



ISSN 2410-6593 (Print)
ISSN 2686-7575 (Online)