Reactions of 1-amino-2-nitroguanidine with 2-aryl(hetaryl)-1-nitro-1-ethoxycarbonyl(benzoyl)ethenes

Reactions of 1-amino-2-nitroguanidine with 2-aryl(hetaryl)-1-nitro-1-ethoxycarbonyl(benzoyl)-ethenes proceed via initial formation the aza-Michael product, are accompanied by liberation of nitroacetic ester (or nitroacetophenone), and result in N-aryl(hetaryl)methylidene-N-(2-nitroguanidino)amines.     

Ion Exchange Recovery of Platinum(IV) from Hydrochloric Acid Solutions in the Presence of Silver(I)

Russian Journal of Physical Chemistry A - The ion exchange sorption of the platinum(IV) chloride complexes in the presence of silver(I) chloro complexes from 2 and 4 M aqueous solutions of...     

Metal Complexes of a Hexameric Network Tetrapyrazinoporphyrazine: II. Complexing Sorption Properties

Coordination of metal ions from aqueous solutions with metal complexes of a hexameric network tetrapyrazinoporphyrazine was studied. These compounds are complexing sorbents; their equilibrium coordination capacity largely depends on the metal occupying the coordination cavity of the porphyrazine fragments and on the external factors: kind of salt being coordinated, solution acidity, etc.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 6, 2005, pp. 1041–1045.Original Russian Text Copyright © 2005 by Korzhenevskii, Markova, Efimova, Koifman, Zelenov.     

Stability of anionic liposome-cationic polymer complexes in water-salt media

Laser microelectrophoresis, dynamic light scattering, and fluorescence and UV spectroscopy are employed to study poly-N-ethyl-4-vinylpyridinium bromide adsorption on the surface of bilayer lipid vesicles (liposomes) formed from mixtures of anionic phosphatidyl serine and electroneutral phosphatidylcholine. It is established that polycation adsorption is accompanied by the neutralization of charges on liposomes and their aggregation. The subsequent addition of a low-molecular-weight salt (NaCl) solution to suspensions of complexes causes them to dissociate into their initial components, while the stability of the complexes with respect to the salt action increases with the fraction of the anionic lipid in the liposome membranes. The data obtained are interpreted from the position of the formation-disintegration of a molecular capacitor, the charge of which is generated by spatially separated anionic lipids located in the bilayer membrane and cationic units of the adsorbed polyamine.     

Reactions between a superoxide anion and alkyl bromides in dimethyl sulfoxide

The activation parameters of the reactions between a superoxide anion (O₂^·−) and alkyl bromides are measured. An ab initio study of the transition states for various mechanisms of this reaction is performed. The mechanism of radical separation in a polar solvent becomes competitive upon an increase in the number of alkyl groups in an alkyl bromide molecule and depends on their arrangement relative to a reaction center.     

Mid-temperature solid oxide fuel cells with thin film ZrO<Subscript>2</Subscript>: Y<Subscript>2</Subscript>O<Subscript>3</Subscript> electrolyte

Data on the mid-temperature solid-oxide fuel cells (SOFC) with thin-film ZrO₂-Y₂O₃ (YSZ) electrolyte are shown. Such a fuel cell comprises a carrying Ni-YSZ anode, a YSZ electrolyte 3–5 μm thick formed by vacuum ion-plasma methods, and a LaSrMnO₃ cathode. It is shown that the use of a combined method of YSZ electrolyte deposition, which involves the magnetron deposition of a 0.5–1.5-μm thick sublayer and its pulse electron-beam processing allows a dense nanostructured electrolyte film to be formed and the SOFC working temperature to be lowered down as the result of a decrease in both the solid electrolyte Ohmic resistance and the Faradaic resistance to charge transfer. SOFC are studied by the methods of voltammentry and impedance spectroscopy. The maximum power density of the SOFC under study is 250 and 600 mW/cm⁻² at temperatures of 650 and 800°C, respectively.     

Solution of an axisymmetric problem of free vibrations of piezoceramic hollow cylinders of finite length by the spline collocation method

An axisymmetric problem of longitudinal free vibrations of piezoceramic hollow cylinders for some types of boundary conditions on the end faces is considered. The lateral surfaces of the cylinder are covered with thin short-circuited electrodes. The polarization of piezoceramics is directed along the axis of the cylinder. Using the method of separation of variables and method of spline collocation along the length of the cylinder, we reduce the problem to a system of ordinary differential equations, which is solved by the method of step-by-step search. We present results of calculations for a PZT 4 piezoceramic cylinder.     

Numerical solution of the propagation problem of longitudinal elastic waves in an orthotropic hollow cylinder

Wave processes in an orthotropic cylinder are analyzed. Harmonic oscillations are considered for which the original problem is reduced to a system of ordinary differential equations. This system is solved by the numerically stable discrete-orthogonalization method. Discrete curves for specific problems are given.Translated from Vychislitel'naya i Prikladnaya Matematika, No. 56, pp. 75–78, 1985.     

Diindolyls

3,5-and 5,5-Diindolyls were obtained from ethyl pyruvate 4-(2-carbethoxy-3-indolyl) phenylhydrazone and ethyl pyruvate 4,4-biphenylyldihydrazone by Fischer cyclization and subsequent saponification and decarboxylation. The formation of 5-phenyl-2-carbethoxyindole, from which 5-phenylindole was obtained, was observed in the indolization of ethyl pyruvate 4,4-biphenylyldihydrazone.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 217–224, February, 1978.