Crystal and molecular structure ofN-phenyl-4-nitrobenzamidoxime

N-Phenyl-4-nitrobenzamidoxime has been studied by X-ray structural analysis. In two crystallographically independent molecules1A and1B, amidoxime groups adopt a planarZ configuration, and these fragments are in ans-trans conformation with respect to the =N-O and C-N(H) bonds; an intramolecular NH...O bond occurs. The nitrophenyl and phenyl groups are rotated with respect to the amidoxime plane [ONCN] by –57 and –32° in1A and –38 and –22° in1B, respectively. The rotation of the fragments about the C(1)-N(2) bond is –28 (1A) and –35° (1B). In crystals, molecules1A and1B are linked in oxime dimers through two intermolecular =N...(HO) hydrogen bonds; dimers form double chains through two NH...(O₂N) hydrogen bonds.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1516–1519, August, 1995.The work was supported by the Russian Foundation for Basic Research (Project No. 93-03-05069).     

QSPR modeling of vitrification temperatures for polyarylene oxides

Prediction of the vitrification temperatures of polyarylene oxides based on optimization of the local invariant correlation weights of molecular graphs for the test sample is statistically characterized by n = 18, r = 0.9288, s = 12.8°C, F = 100.Original Russian Text Copyright © 2004 by A. A. Toropov, I. N. Nurgaliev, O. I. Balakhonenko, N. L. Voropaeva, I. N. Ruban, and S. Sh. RashidovaTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 741–747, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Structural Characteristics of Hydrated Complexes of Aminoacids in Aqueous Solutions

Aqueous solutions of nine α-aminoacids were studied in a diluted range of concentrations (from 0. 01 m to 0.1 m) at 5°C, 15°C, 25°C, 35°C, and 45°C based on the model that uses molar adiabatic compressibility (β _s V _m ) as a measure of hydration of the solute. For the resulting hydrated complexes of aminoacids, structural characteristics have been determined. At increased concentrations of the acid, variation of its hydration number is the chief factor affecting the molar compressibility of the hydrated complex.Original Russian Text Copyright © 2004 by V. N. Afanasiev, E. Yu. Tyunina, and V. V. Ryabova__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 883–888, September–October, 2004.     

Crystalline β Modification of (BEDT-TTF)<Subscript>2</Subscript>Br<Subscript>0.12</Subscript>Cl<Subscript>1.88</Subscript>I

The structure of the crystalline β’ modification of a radical cation salt of bis(ethylenedithio)tetrathiafulvalene with mixed dihalogen iodide (BEDT-TTF)₂Br_0.12Cl_1.88I (I) was investigated by single crystal X-ray diffraction. Triclinic structure of I (space group , a = 6.638 Å, b = 9.779 Å, c = 12.920 Å; α = 87.24°, β = 79.10°, γ = 81.37°) was solved by direct methods and refined in a full-matrix anisotropic approximation to R = 0.030 using all 3897 measured independent reflections (CAD-4 automatic diffractometer, λMoK _α). In the crystal structure of I the mixed Cl*-I-Cl* anion occupies the inversion center i(000), its terminal atom having a composition Cl* = Cl_0.94Br_0.06. The semi-radical cation (C₁₀H₈S₈)^1/2+ has one of two ethylene groups disordered.Original Russian Text Copyright © 2004 by A. N. Chekhlov__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 960–965, September–October, 2004.     

Development of the specific surface areas of natural coal in the course of thermolysis in the presence of potassium hydroxide

The development of the surface of natural coal from Donets field in the course of thermolysis with KOH was studied. The dependences of the specific surface area of coal containing 90% carbon on the activation time, temperature (400–800°C), and KOH/coal ratio (0.75–4.5 g g^–1) were determined. The effect exerted on the development of the porous coal structure by low-temperature (20±2°C) oxidative modification causing formation of oxygen functional groups and reorganization of the coal three-dimensional structure was studied.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 9, 2004, pp. 1452–1455.Original Russian Text Copyright © 2004 by Tamarkina, Kucherenko, Shendrik.     

Synthesis and characterization of new poly[phenylquinoxaline(ether)imides]

A series of new aromatic poly[phenylquinoxaline(ether)imides] were synthesized by solution polycondensation of aromatic diamines containing preformed phenylquinoxaline groups with dianhydrides having ether linkages and isopropylidene or hexafluoroisopropylidene units. All polymers are readily soluble in polar organic solvents (N-methylpyrrolidinone, DMF, dimethylacetamide) and in less polar liquids such as chloroform. Very thin coatings were deposited onto silicon wafers. According to atomic force microscopy, they had a smooth, pinhole-free surface. The polymers showed high thermal stability with decomposition temperatures above 470 °C and glass transition temperatures in the range of 210–238 °C, being thus characterized by a large gap between the glass transition and decomposition temperatures.Based on the report presented at the International Conference Modern Trends in Organoelement and Polymer Chemistry dedicated to the 50th year anniversary of the A. N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences (Moscow, May 30–June 4, 2004).Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1952–1957, September, 2004.     

X-ray structural study of alkaloids. VII. Structure and absolute configuration of severidine

A physicochemical and complete x-ray structural investigation of the new alkaloid severidine isolated from the epigeal part ofKorolkowia sewerzowii Regel has been performed. The crystals were investigated in the form of severidine hydrochloride, C₂₇H₄₃NO₅·HCl, rhombic,a=12.642, b=12.882, c=16.621 Å, z=4, space group P2₁2₂2₁, at –120°C. The structure was interpreted by the direct method and was refined to R=0.039. The hydrogen atoms were revealed. The absolute configuration was established by means of the Hamilton test. The skeleton of the cation is constructed of bicyclic and tricyclic fragments linked by an ordinary C-C bond. All the rings have the chair conformation. The bond lengths and valence angles are normal.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. A. N. Nesmeyanov Institute of Organometallic Compounds, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 342–349, May–June, 1981.     

Active centers on the surface of thermoactivated silica. Their reactivity toward organoaluminum compounds

Interaction between organoaluminum compounds (triethylaluminum, ethoxydiethylaluminum, and diethoxyethylaluminum) and the surface of silica activated at various temperatures (200–800 °C) was studied by IR spectroscopy, mass spectrometry, and quantum chemistry. Formation of structural silanon defects on the surface of silica activated at 800 °C was considered. It was established that the fraction of terminal silanol groups involved in the interaction with organoaluminum compounds on the surface of silica thermoactivated above 600 °C is low, and siloxane bonds and structural surface defects play a determining role. The thermodynamic favorability of coordination of organoaluminum compounds on these active surface centers is shown. The structure and routes of decomposition of aluminum-containing surface intermediates were studied.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1906–1911, October, 1995.The work was financially supported by the Russian Foundation for Basic Research (Project No. 94-03-08847).     

Beitrag zur Kenntnis der Systeme Titan—Chrom—Stickstoff,Zirkonium—Chrom—Stickstoff und Hafnium—Chrom—Stickstoff

Zusammenfassung Das ternäre System Ti–Cr–N wurde bei 1000° C und 1200° C mit Hilfe von metallographischen und röntgenographischen Methoden untersucht. Die Mononitride TiN und CrN bilden eine lückenlose Reihe von Mischkristallen; dieVegardsche Kurve weicht schwach negativ von der Geraden ab. Es konnte keine ternäre Verbindung gefunden werden. Für 1000° C wird ein Vorschlag für einen isothermen Schnitt durch das System Ti–Cr–N entworfen.Die Untersuchungen in den Systemen Zr–Cr–N und Hf–Cr–N beschränkten sich auf den Bereich der pseudobinären Schnitte ZrN/CrN und HfN/CrN. Um die Stabilität des weniger stabilen CrN sicherzustellen, wurden bei den Versuchstemperaturen folgende Stickstoffdruck-Bedingungen gewählt: 1 at N₂ bei 1000° C, 30 at N₂ bei 1200° C und 250 at N₂ bei 1400° C.Die isotypen Phasen ZrN und CrN zeigen eine Mischungslücke; aus dem Temperaturverlauf der Mischungslücke kann angenommen werden, daß sie sich bei 1440° C und 50 Mol% ZrN schließt.Im pseudobinären System HfN–CrN konnte im untersuchten Temperaturbereich lückenlose Mischbarkeit zwischen den Komponenten festgestellt werden. Eine Entmischung tritt, wenn überhaupt, nur bei Temperaturen unterhalb 1000° C auf. DieVegardkurve der Gitterparameter der Mischkristalle zeigt eine schwach positive Abweichung von der Geraden.

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About the ternary systems titanium—chromium—nitrogen, zirconium—chromium—nitrogen and hafnium—chromium—nitrogen

The ternary system Ti–Cr–N has been investigated by X-ray powder technique and by metallographic methods in two isothermic sections at 1000° C and 1200° C. The isotypic mononitrides TiN and CrN form a complete series of solid solutions, theVegard's curve shows a slight negative deviation from linearity. No ternary compound could be observed. A tentative phase diagram for an isothermic section at 1000° C is given.Investigation of the systems Zr–Cr–N and Hf–Cr–N was restricted to the pseudobinary sections ZrN–CrN and HfN–CrN. To ensure the stability of the less stable component (CrN) the following pressure conditions were chosen: 1 atm N₂ at 1000° C, 30 atm N₂ at 1200° C, 250 atm N₂ at 1400° C. The isotypic compounds ZrN and CrN exhibit a miscibility gap, which diminishes with increasing temperature. The cirtical point can be estimated to be at 1440° C and 50 mol% ZrN. In the pseudobinary system HfN–CrN a complete series of solid solutions could be observed. A miscibility gap should occur, if ever, at temperatures below 1000° C.Vegard's curve for the lattice parameters of the solid solutions (Hf, Cr)N shows a slight positive deviation from linearity.

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Herrn Prof. Dr.H. Nowotny gewidmet.

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Auszug aus der von der Fakultät für Naturwissenschaften der T. H. Wien approbierten Doktor-Dissertation des Herrn Dipl.-Ing.F. Petter.     

Zum Aufbau der Systeme V—(Fe,Co, Ni)—N

The constitution of the ternary systems V–Fe–N, V–Co–N, and V–Ni–N has been investigated by X-raymethods, metallographically and partly by microprobe analysis. Isothermal sections are presented for 1100°C and 1200°C respectively. Ternary complex nitrides have been observed in the systems V–Co–N and V–Ni–N. The compounds with formula V₄Co₂N (a=10.88–10.83±0.01 Å) and V₄Ni₂N (a=10.88–10.86±0.01 Å) crystallize with the partly filled Ti₂Ni-structure.

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Synthesis,structure, and characteristics of 1,2-dichlorovinyl alkyl ketones

A method of alkyl 1,2-dichlorovinyl ketones preparation from acyl halides and 1,2-dichloroethylene was developed. The configurational equilibrium and electronic structure of alkyl 1,2-dichlorovinyl ketones was investigated by IR, ¹H and ¹³C NMR spectroscopy, by measuring dipole moments, and by quantum-chemical calculations using methods RHF and B3LYP in the basis 6–311++G (d,p). Alkyl 1,2-dichlorovinyl ketones are stable in the Z, s-cis-configuration where the olefin proton is involved into an intramolecular hydrogen bond with the oxygen of the carbonyl group. Reaction of 1,2-dichlorovinyl ketones with alkylhydrazines afforded 1-alkyl-3-alkyl-4-chloropyrazoles. The reaction of alkyl 1,2-dichlorovinyl ketones with 1,1-dimethylhydrazine involved dehydrochlorination and afforded 1,1-dimethylhydrazinium hydrochloride and a mixture of compounds with uncertain structure.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 11, 2004, pp. 1632–1640.Original Russian Text Copyright © 2004 by Bozhenkov, Leckovskaya, Larina, Ushakov, Dolgushin, Mirskova.     

Apparent molal heat capacities of organic solutes in water. V. aminoalcohols,aminoethers, diamines,and polyethers

Apparent molal heat capacities of 20 organic uncharged compounds in aqueous solution have been determined at 25 and 40°C. The substances studied include mono- and polyfunctional ethers, and bifunctional open-chain compounds like aminoalcohols, aminoethers, and diamines. The results obtained support the presence of interaction between water and the hydrophilic groups –O–, –NH₂, –NH–, and , and evidence indicates that these interactions strongly depend on the molecular structure of the compound containing the functional group.     

New alkaloids ofDipthychocarpus strictus

New alkaloids with mp 57–59°C and diptamine have been isolated from the seeds and epigeal part ofDipthychocarpus strictus collected in Chimkent Province (KazSSR). It has been established that the base with mp 57–59°C has the structure of N,N-di(6-methylthiohexyl)urea, while diptamine is N-isopropyl-N-(7-methylsulfonylheptyl)urea.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedeninii, No. 3, pp. 363–365, May–June, 1980.     

Crystal Structure of 4,7,13,16,21,24-Hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane Semihydrate Oxonium Tribromide

The crystal structure of 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo-[8.8.8]hexacosane semihydrate oxonium tribromide, [H₂(2.2.2-Crypt)·0.55H₂O]²⁺·H₃O⁺·3Br⁻ (I) was determined by XRD analysis. The triclinic structure of I (space group P , a = 10.026 Å, b = 11.292 Å, c = 13.115 Å, α = 78.37°, β = 72.11°, γ = 77.50°, Z = 2) was solved by direct methods; full-matrix least-squares refinement in an anisotropic approximation converged to R = 0.055 for all 4057 independent reflections collected (CAD-4 automatic diffractometer, λCuK _α).Original Russian Text Copyright © 2004 by A. N. Chekhlov__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1136–1141, November–December, 2004.     

Condensation of carboranes-12 with tri- and tetrachloroethylenes

The interaction ofortho-, meta-carboranes with tri- and tetrachloroethylene was investigated at 380°C in the absence of radical sources and at 150–200°C in the presence oftert-butyl peroxide.A. N. Nesmeyanov Institute of Heteroorganic Compounds, Russian Academy of Sciences, Moscow 117813. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 4, pp. 1020–1023, April, 1992.     

Thermodynamic properties of the first to fifth generations of carbosilane dendrimers with allyl terminal groups

Temperature dependences of the specific heats, characteristic temperatures, and enthalpies of physical transformations of the first to fifth generations of carbosilane dendrimers with allyl terminal groups were studied using an adiabatic vacuum calorimeter in the temperature range 6—340 K. The error of measurements was, as a rule, about 0.2%. Thermodynamic characteristics of physical transformations of the dendrimers were determined and their thermodynamic functions C _p°(T), H°(T)—H°(0), S°(T)—S°(0), and G°(T)—H°(0) were calculated for the temperature range 0—340 K. The thermodynamic functions of the dendrimers are linearly related to their molecular weights, the number of allyl groups on their outer spheres, and the number of moles of diallylmethylsilane per mole of the dendrimers formed. Additive dependence of the properties of the dendrimers on their chemical composition and structure indicates that the energy of interaction between structural fragments of the dendrimers is independent of the dendrimer generation number. The fractal dimensions, D, of all dendrimers studied in this work are 1.2—1.3 in the temperature range 30—50 K, thus indicating a chain-layered structure of the dendrimer glasses.     

Study of Palladium Complexes with Chitosan and Its Derivatives as Potential Catalysts for Terminal Olefin Oxidation

FTIR spectroscopy and XPS are used to study palladium complexes with various forms of chitosan: initial and modified by glutaric aldehyde. IR bands are identified that are related to the Pd–N and Pd–O bonds. A difference between the spectra of complexes obtained by the methods of adsorption and coprecipitation of chitosanium hydrochloride with the tetrachloropalladate ion is found. It is shown that the systems studied can be used as catalysts for terminal olefin oxidation by oxygen in the presence of H₂O₂. In the course of the reaction, the complexes undergo redox transformations without breaking the structure of the complex or metal transfer to the reaction mixture. The use of heterogenized Pd(II) complexes as catalysts in terminal olefin oxidation leads to the formation of oxidation and isomerization products, similarly to the case of homogeneous oxidation.     

Method of determination of dielectric relaxation characteristics of plasticized polystyrenes on the basis of calorimetric glass temperature

The dielectric loss measurements of different polystyrenes (fractions and blends) with different molecular weights (M _n 2000–125000 g/mol) were carried out in the frequency range 10^–2–10⁶ Hz and the temperature range of the glass process (60°–135°C, depending on the molecular weight). The measurements of the pure fractions showed that the half-width of the glass relaxation process of the different polystyrenes can be correlated by a straight line, if they are plotted versus the relaxation frequency maxima of the glass process, regardless of the difference in both their molecular weight and glass transition temperature. Moreover, the fine structure of the shape of the glass process of polystyrenes with different molecular weights was found to be the same when the glass process appears at the same relaxation frequency range. The addition of oligostyrenes or low molecular <10% wt additives to the high molecular weight polystyrene did not influence the shape of the glass process. The calorimetric glass transition temperature of polystyrene was found to be only dependent on the number average molecular weight as well as on the number of end groups, but not on the molecular weight distribution. The obtained experimental results were correlated to develop a method for the estimation of the dielectric relaxation characteristics (relaxation frequency as well as the shape parameters) of the glass process of plasticized polystyrenes based on the calorimetric glass transition temperature. A method for the analysis of the dielectric relaxation curves of mixtures of label and polymer is suggested.     

The structure of gummosin

Summary From the neutral fraction of an acetone extract of the roots of plants of the genusFerula,F. gummosa Boiss.,F. pseudoreoselinum Rgl. et Schmalh. (K-Pol.) andF. Samarkandica Eug. Kor., we have isolated a coumarin gummosin with the composition C₂₄H₃₀O₄, mp 176–177°C, [a]_D –54°C. The structure of gummosin corresponds to formula (III).With respect to structure, gummosin is a spatial isomer of farnesiferol A; it differs from the latter by the fact that the secondary OH group in gummosin is axial.Khimiya Prirodynkh Soedinenii, Vol. 2, No. 6, pp. 383–387, 1966     

Mechanism and Relationships of Chemical Degradation of Rigid Polyurethane Foam

The regular trends in chemical degradation of rigid polyurethane foam under the action of oxypropylated hydroxy compounds were studied. The molecular-weight characteristics, functionality with respect to 4,4′-diphenylmethane diisocyanate and OH groups, viscosity, and the content of terminal OH groups of alcoholysis products at temperatures from 150 to 220°C were determined. A mechanism of degradation of the network structure of rigid polyurethane foam was suggested.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 5, 2005, pp. 840–845.Original Russian Text Copyright © 2005 by Galimzyanova, Bakirova, Valuev, Zenitova.