Phase transition and superconductivity high-T<Subscript>c</Subscript> oxides

On the basis of new experimental studies of specific heat, magnetic properties and thermal expansion, it was shown that dielectric-metal phase transitions were the consequence of delocalization of the heavy holes located on metalapical oxygen bonds in the high-T_c oxide systems. The ordered arrays of such holes (CDW) results in the dielectric gaps in electron spectrum and anomalous negative thermal expansion. The free carriers introduced by doping can couple through excitations of these localized holes, (local bosons). The high-T_c superconductivity will possess anomalous H_c2(T) dependence and γ-type specific heat jump at T_c. This local bosons model is the basis for explanation of the obtained experimental data.     

Reaction of 3-Benzoyl-2,3-dibromopropionic Acid with Substituted ortho-Phenylenediamines

3-Benzoyl-2,3-dibromopropionic acid reacts with 4-substituted o-phenylenediamines to give 3-aryl-2-carboxymethylene-1,2-dihydroquinoxalines.     

The use of the consecutive adsorption of pyridine bases and carbon monoxide in the IR spectroscopic study of the accessibility of acid sites in microporous/mesoporous materials

A new approach to the evaluation of the accessibility of acid sites in microporous/mesoporous materials is developed and tested using a series of dealuminated mordenites. This approach is based on an IR-spectroscopic study of the consecutive adsorption of substituted alkylpyridines (pyridine, 2,4,6-trimethylpyridine, and 2,4,6-triethylpyridine) and carbon monoxide. This method allowed us to determine the strength and number of acid sites with various degrees of accessibility. The adsorption of 2,4,6-triethylpyridine on various types of materials is studied. The extinction coefficients of alkylpyridines are determined using a McBain balance placed in a cell for IR-spectroscopic measurements. Original Russian Text N.S. Nesterenko, F. Thibault-Starzyk, V. Montouilliout, V.V. Yushchenko, C. Fernandez, J.-P. Gilson, F. Fajula, I.I. Ivanova, 2006, published in Kinetika i Kataliz, 2006, Vol. 47, No. 1, pp. 45–53.     

Alkylation ofβ-diketones of the hexahydroindan series and their enamines

Conclusions The reactions of hexahydro-1,3-indandlone with ammonia and some amines were studied, and the structures of the products formed were proved. In the alkylation of-diketones of the hexahydroindan series and their enamines under the usual conditions C-alkylation products are not formed.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1214–1218, July, 1966.     

Method and apparatus for vacuum-thermic extraction (VTE) of toxic and essential elements from soils in oxidation-reduction medium in connection with analytical applications — I

A method is presented for simultaneous separation of traces of toxic and essential elements from soils. The method is based on programmed vacuum-thermic extraction of the elements in an oxidation-reduction medium. Under optimal conditions of temperature and pressure Pb, Zn, Cd, Bi, Tl, As, Sb, Te, Mo, Hg and Re are distilled or sublimated in elementary state or as oxides. A simple quartz apparatus is proposed. The elements extracted from matrix are dissolved in nitric acid and determined by AAS or OES with ICP excitation.     

Acid–Basic Properties of Al(III), Ga(III), and In(III) Complexes with Octaphenyltetraazaporphine

Al(III), Ga(III), and In(III) complexes with octaphenyltetraazaporphine and halide axial ligands of the composition [(X)MTAP] (X = F, Cl, Br) and In(III) complexes with bidentate ligands of the composition [(Y)InTAP] (Y = nitrite (NO₂) and 2,3-naphthodiolate (NpO₂)) were synthesized. The acid–basic properties of the complexes were studied in the proton-donor media and the concentration stability constants of the acidic forms obtained at the first protonation stage were determined. The effect of the nature of a metal and extra ligand on the basic properties of meso-nitrogen atom in macrocyclic ligand was discussed.