Crystal and Molecular Structure of <Emphasis Type="Italic">Bis</Emphasis>(2,3-pentamethylene-3,4-dihydro-4-oxoquinazolinium) Tetrachlorocuprate(II) Sesquihydrate

The structure of bis-(2,3-pentamethylene-3,4-dihydro-4-oxoquinazolinium) tetrachlorocuprate (II) sesquihydrate, (C₁₃H₁₅N₂O)₂[CuCl₄]·1.5H₂O, was determined by single crystal X-ray diffraction. In contrast to the previously studied analogs, the compound contains crystallization water molecules.Original Russian Text Copyright © 2004 by K. K. Turgunov, B. Tashkhodzhaev, L. V. Molchanov, and Kh. M. Shakhidoyatov__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 955–959, September–October, 2004.     

Polynomial Quantization on Rank One Para-Hermitian Symmetric Spaces

We construct the polynomial quantization on the space G/H where G=SL(n,R),H=GL(n–1,R). It is a variant of quantization in the spirit of Berezin. In our case covariant and contravariant symbols are polynomials on G/H. We introduce a multiplication of covariant symbols, establish the correspondence principle, study transformations of symbols (the Berezin transform) and of operators. We write a full asymptotic decomposition of the Berezin transform.     

On the level density of random band matrices

Translated from Matematicheskie Zametki, Vol. 50, No. 6, pp. 31–42, December, 1991.     

Esters of Substituted 2,3,7-Triazabicyclo[3.3.0]oct-3-ene-4-carboxylic acids and 1,2,7-Triazaspiro[4.4]non-2-ene-3-carboxylic acids in Alkylation and Acylation

Esters of substituted 2,3,7-triazabicyclo[3.3.0]oct-3-ene-4-carboxylic acids react with acetone in the presence of hydrogen chloride (bromide) affording esters of substituted 2-(1,1-dimethyl-3-oxobutyl)-2,3,7-triazabicyclo[3.3.0]oct-3-ene-4-carboxylic acids. Reactions of esters of substituted 2,3,7-triazabicyclo[3.3.0]octa-1(5),3-diene-4-carboxylic acids with 1-adamantanol in trifluoroacetic acid resulted in esters of substituted 2-(1-adamantyl)- 2,3,7-triazabicyclo[3.3.0]octa-1(5),3-diene-4-carboxylic acids.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 2, 2005, pp. 252–263.Original Russian Text Copyright © 2005 by Stepakov, Molchanov, Kostikov.     

Reaction of substituted spiro[1,2,3,4-tetrahydronaphthalene-2,3′-(1′-pyrazolines)] with chlorinating reagents

In reaction of 4′-arylspiro[1,2,3,4-tetrahydronaphthalene-2,3′-(1′-pyrazolin)]-1-ones with N-chlorosuccinimide formed spirocyclic substituted 3-chloro-1-pyrazolines that lost nitrogen at heating transforming into spirocyclic chlorocyclopropanes. The reaction of the same pyrazolines with chlorine led to the formation of spirocyclic gem-dichlorocyclopropanes.     

Viscoelastic Properties of Aqueous Anionic Surfactant (Potassium Oleate) Solutions

The dependence of the viscosity of potassium oleate salt-containing solutions on the surfactant concentration is studied. The potassium oleate concentration corresponding to the formation of semidilute solution of cylindrical micelles is determined. It is shown that, in the semidilute regime, one can distinguish two regions characterized by different exponential dependences of the viscosity on the surfactant concentration. The first region corresponds to unbreakable micelle chains that have no time to be destroyed during the characteristic time of reptation, whereas the second region corresponds to “living chains” whose lifetime is shorter than the characteristic time of reptation. In the second region, rheological properties of semidilute potassium oleate solutions are adequately described by the Maxwell model with a single relaxation time.     

Crystal structure of La3Nb0.5Ga5.5O14 at 20 K

The atomic structure of La₃Nb_0.5Ga_5.5O₁₄ single crystals (space group P321, R = 2.21%, R _w = 2.31%) at 20 K was determined using X-ray diffraction. A comparative analysis of the structural characteristics determined at temperatures of 293 and 20 K did not reveal a noticeable redistribution of bond valences that could be considered precursors of a possible phase transition accompanied by the reduction of the symmetry of the crystal. The assumption was made that the anomalous behavior of the permittivity e ₃₃ of the La₃Nb_0.5Ga_5.5O₁₄ single crystals is associated with the decrease in the possible relative displacements of the Ga(1) and Nb atoms occupying the cation position with point symmetry 32 in a 1: 1 ratio.     

Ba1−x R x F2 + x Phases (R = Gd-Lu) with distorted fluorite-type structures—products of crystallization of incongruent melts in the BaF2-RF3 Systems (R = Gd-Lu). III. Defect Ba0.75Lu0.25F2.25 structure. A new {Lu8[Ba6F71]} supercluster of defects

The structure of Ba_0.75Lu_0.25F_2.25 crystals grown from melt has been studied by X-ray diffraction analysis (4729 measured reflections, 269 independent reflections with I > σ (I), R = 1.1%, R _w = 0.7%). The crystals are crystallized in the cubic system, sp. gr. Pm $\bar 3$ m, with the lattice parameter a = 5.9870(9) Å. A new complex of defects is singled out—a supercluster of the composition {R ₈[Ba₆F₇₁]}. This supercluster differs from the well-known rare earth octahedral supercluster of the composition {Ba₈[R ₆F_68-69]} because its nucleus is formed not by RE cations but by an alkali earth cation, Ba. The {R ₈[Ba₆F₇₁]} supercluster has a configuration close to that of the [B₁₄F₆₄] fragment of the fluorite structure and can replace the latter isomorphously. The model of the Ba_0.75Lu_0.25F_2.25 crystals consisting of coherently intergrown isostructural microphases having different chemical compositions is characterized by the good agreement of the calculated and experimentally determined occupancies of the F^1? positions. The comparison of the Ba_0.8Yb_0.2F_2.2 (phase studied earlier) and Ba_0.75Lu_0.25F_2.25 structures demonstrates the evolution of the defect structure along the series of rare earths with the corresponding change of the sp. gr. Fm $\bar 3$ m by the sp. gr. Pm $\bar 3$ m.