1,2-Dioximes in the trofimov reaction

3,3′-Dimethyl-1,1′-divinyl-2,2′-dipyrrole was obtained during the reaction of 3,4-hexanedione dioximes with acetylene under pressure in the potassium hydroxide-DMSO system. In the case of 1,2-cyclohexanedione dioxime 2,2′-dipyrrole and 2-pyridyl-and 2-acylpyrroles were isolated. α-Benzil and α-furil dioximes give 3,4-diphenyl-and 3,4-di(2-furyl)-1,2,5-oxadiazoles respectively in addition to their mono-and divinyl derivatives. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 39–46, January, 2006.     

Peculiarities of solvation interaction of water-soluble metallophthalocyanines with ethanol

Physico-chemical characteristics of molecular complexes for water-soluble metallophthalocyanines with alcohol were obtained by the method of thermogravimetric analysis. The change of aggregation state of metallophthalocyanines in aqueous alkaline solutions which is due to the ethanol additions was explained taking into consideration the results of thermogravimetric analysis of metallophthalocyanines crystallosolvates with ethanol.     

Structure and properties of solid solutions based on bismuth niobate Bi<Subscript>3</Subscript>NbO<Subscript>7</Subscript>

Solid solutions Bi₃Nb_1–yW_yO_{7 ± δ}, Bi₃Nb_1–yV_yO_{7 ± δ}, Bi₃Nb_1–yFe_yO_{7 ± δ} (y = 0.1–0.5; Δy = 0.1), and Bi_3–xY_xNb_1–yW_yO_{7 ± δ} (x = 0.05, 0.1; y = 0–0.3; Δy = 0.1) have been studied. The homogeneity ranges of the solid solutions and crystal-chemical parameters have been determined by means of X-ray powder diffraction. The electrical conductivity of sintered samples has been studied by impedance spectroscopy. The joint introduction of yttrium and tungsten into the niobium sublattice does not lead to an increase in the conductivity of solid solutions, and the change of the dopant type has no noticeable effect on this conductivity.     

Sorbents based on asbestos with a layer of an hydroxyethylcyclam derivative of PVC containing aquacomplexes of sulfuric acid or sodium hydroxide with aza-crown groups

Aquacomplexes of sulfuric acid and sodium hydroxide with aza-crown groups are synthesized in cavities of a sorbent from the porous layer of a PVC cyclam-derivative grafted onto fibers of asbestos fabric. The structure of sorbents with complexes is studied and their adsorption characteristics are determined. It is shown that the affinity of the developed surface toward ethanol, benzene, and hexane depends on the nature of complexes in the pore walls, and the volume of cavities formed as a result of the pores on the developed asbestos surface being coated with networks of aza-crown groups is larger than that of cavities with walls of aza-crown groups in the layers of a PVC cyclam derivative. Indicators of H⁺- and OH^–-conductivity of sorbents with complexes as electrochemical bridges are determined. It is shown that the major part of H⁺- and OH^–-ions moves through complexes with aza-crown groups in the region of cavities formed of pores on the surface of asbestos.     

Materials based on carbon-filled porous layers of PVC cyclam derivatives cross-linked with the surfaces of asbestos fabric fibers

The synthesis of bilayer materials with porous upper layers composed of PVC hydroxyethylcyclam derivatives filled with carbon and a layer consisting of hydroxyethylcyclam, cross-linked via Si–O–C groups with the silica chains of a developed surface of asbestos fabric, is described. The aza-crown groups in these materials are bound with aqua complexes of H₂SO₄ or NaOH. The structure of the materials is examined, their adsorption characteristics are determined, and the rate of motion of H⁺ or OH^– ions in electrochemical bridges is measured, while the formation of H₂ and O₂ in their cathodic and anodic polarization is determined as a function of voltage. It is shown that the upper layer of these materials is adsorption-active and electronand H⁺- or OH^–- conductive, while the bottom layer is only H⁺- or OH^–- conductive; through it, the upper layer is supplied with the H⁺ or OH^– ions needed for the regeneration of the aqua complexes broken down to H₂ and O₂ on carbon particles.     

Physicochemical properties of precursors of Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–ZrO<Subscript>2</Subscript> oxide ceramics prepared by electrochemical method

Scanning electron microscopy, X-ray, and thermal analysis are used to examine the structure and properties of dispersive systems based on aluminum and zirconium oxides prepared electrochemically. The effect the conditions of synthesis have on the structure and morphology of Al₂O₃–ZrO₂ particles is studied. It is shown that the effect of an electric field on the reaction medium allows us to adjust the physicоchemical properties and morphology.     

Evaluation of Stability of Mesoporous Silica Nanoparticles and Their Further Formulation in Tablet Form

Mesoporous silica nanoparticles have been widely investigated as drug delivery systems. The present study evaluated physical stability of indomethacin loaded mesoporous MCM-41 nanoparticles. The size, polydispersity index, zeta-potential, and drug loading degree of nanoparticles were determined immediately after their preparation and after 6 months storage at 25°C in dry state. The results showed insignificant changes in these parameters, suggesting high stability of nanoparticles and loaded indomethacin. The nanoparticles were formulated in tablets by direct compression. The low friability indicated good resistance during handling and storage. The formulation of the nanoparticles into tablets decreased the initial release of indomethacin.     

Interaction of microcracks with a macrocrack yielded in a narrow strip

Plastic zone growth of collinear cracks has had a longstanding interest in ductile fracture. This work further considers yield zone growth in an isotropic, homogeneous elastic–perfectly plastic infinite plate containing a macrocrack with several neighboring microcracks. Normal loading is considered at distances far away from the cracks. The strip yield is adopted where the plastic zone is assumed to be confined to two narrow strips extending from the ends of a finite length crack while the microcracks are assumed to be elastic. The plastic zone length and crack opening displacement are found from asymptotic solution and compared with finite element solution.