The influence of fullerene additives on the structure of polystyrene films

It was shown by electron microscopy and X-ray diffraction that a polystyrene solid with a three-level hierarchical structure was formed when the solvent was evaporated from a solution of polystyrene in o-xylene (polystyrene molecules stuck together united to form a framework). The kinetics of the transformation of formerly dissolved molecules into aggregates could be described by a Fokker-Planck-type equation. Fullerenes introduced into a solution of polystyrene in amounts less than 0.1 wt % transformed aggregated polystyrene molecules into nanocrystals and accelerated the formation of aggregates. The influence of fullerenes on the kinetics of the processes could be correctly described in the continuum approximation taking into account aggregation rate fluctuations. Original Russian Text ? O.V. Alekseeva, N.A. Bagrovskaya, S.M. Kuz’min, A.V. Noskov, I.V. Melikhov, V.N. Rudin, 2009, published in Zhurnal Fizicheskoi Khimii, 2009, Vol. 83, No. 7, pp. 1320–1326.     

The electrical conductivity of a network polymer based on tetraphenylcalix[4]resorcinarene

The electrical conductivity of a polymer based on tetraphenylcalix[4]resorcinarene in the form of H⁺, Na⁺, Li⁺, Ag⁺, and Ba²⁺ cations was measured, and the self-diffusion coefficients and activation energies of metal cation diffusion in the polymer phase were calculated. It was found that the specific conductivity of the polymer in the form of Ba²⁺ cations was 0.004 S/cm, increased to 0.01 S/cm when the polymer was in the form of singly-charged metal cations, and became as high as 0.2 S/cm when the polymer was transformed into the H form. It was shown that the self-diffusion coefficients of metal cations in the polymer phase increased in the sequence Ba²⁺ < Ag⁺, Li⁺ < Na⁺. The conclusion was made that, over the temperature range 298–333 K, the activation energy of metal cation diffusion in polymer was 14–15 kJ/mol and did not obviously depend on the cation charge. Original Russian Text ? G.N. Al’tshuler, E.V. Ostapova, 2009, published in Zhurnal Fizicheskoi Khimii, 2009, Vol. 83, No. 6, pp. 1171–1174.     

Recording medium based on a polymer azobenzene complex with cobalt for polarization holography

We have recorded holograms in films of a 4-methacroyloxy-(4′-carboxy-3′-hydroxy)-2-chloroazobenzene polycomplex with cobalt, for parallel and orthogonal orientation of the light beam polarization. The increase in the diffraction efficiency of the holograms and the decrease in their relaxation time in the case of orthogonal polarization compared with the case of parallel polarization of the recording light beams are connected with features of the structural rearrangement of the polymer matrix. We hypothesize that the information-related characteristics of the recording medium created can be controlled by external electric or magnetic fields, due to the presence of magnetic metal ions in the composition of the medium. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 45, No. 1, pp. 46–49, January–February, 2009.     

The standard enthalpies of formation of 4,4′-dinitrodiphenyl ether

The energy of combustion and the standard enthalpy of formation of 4,4′-dinitrodiphenyl ether were determined experimentally for the first time. Original Russian Text ? S.V. Mel’khanova, S.M. Pimenova, I.A. Nesterov, 2009, published in Zhurnal Fizicheskoi Khimii, 2009, Vol. 83, No. 7, pp. 1399–1400.     

Concerted processes in supercritical fluids

The possibility of obtaining concerted mechanisms of chemical activation in supercritical fluids (SCFs) with the formation of a multicenter general transition state that includes a group of reagent atoms in which the subsequent breaking of chemical bonds and the formation of new chemical bonds start and proceed simultaneously is discussed. Two processes are considered that can occur only in SCF media: the reduction of anthracene in an isopropyl alcohol SCF and the impregnation of the photochromic compound spiroanthrooxazine (SAO) in a polycarbonate matrix in SC CO₂ accompanied by an irreversible conformational rearrangement of the SAO structure. Concepts of the possible dependence of the concerted mechanism of the considered processes on the intertwining or entanglement of electron subsystems in forming multicenter transition states are developed. The decisive role of the electromagnetic component of a physical vacuum in obtaining a high degree of correlation in systems of entangled electrons is discussed.     

Features of the photochromic behavior of spiroanthrooxazine in solutions

The photochromic properties of 1,3,3-trimethylspiro[indolin-2,3-3H-anthraceno[2,1-b][1,4]-oxazine] (SAO) in solutions of different polarity [n-BuOH and petroleum ether (PETh)] were studied. It was established that the quantum yield of the photocoloration AB and the energy of activation of the thermal decolorization E_a in the PETh depend on the temperature; this is not the case in n-BuOH. The luminescence properties of SAO were investigated. It was found that the spectrum of the excitation of the luminescence in PETh depends on the temperature. These features, as well as the slower thermal decolorization of the colored form of SAO in PETh by comparison with the solutions in n-BuOH, are explained by the presence of dimers of the SAO molecules in nonpolar media in the temperature range investigated (77–300 K), whereas the SAO molecules already occur in the monomeric state at 150 K in the polar n-BuOH.N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow. Branch of the Institute of the Physics of Solids and Semiconductors, Academy of Sciences of Belarus, 211177 Vitebsk. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 93–98, January, 1992.     

Bismuth(III) complexing with some N- and N,N-substituted thioureas

Stability constants at ionic strength I = 2 and 293 K were determined spectrophotometrically for multiligand bismuth(III) complexes with thiourea (Tu), N-phenylthiourea (Ptu), N-phenyl-N′-propylthiourea (Pptu), N,N′-diphenylthiourea (Bptu), and N-allyl-N′-propylthiourea (Aptu). The protonation constants of these ligands in perchloric acid solutions were also determined. The stability of the listed complexes changes in the following order of ligands: aptu > tu > pptu > ptu > bptu. This order coincides with the order of changing protonation constants. Original Russian Text ? N.N. Golovnev, G.V. Novikova, and A.A. Leshok, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 2, pp. 374–376.     

Influence of the composition of double oxyhydrates MxMn1?xO2·nH2O (Mz+ = Zr, Al, Sn, Ti) on the sorption activity and cation mobility

Adsorption of Cr(VI) on Fe₂O₃ from model solutions with various Cr(VI) concentrations was studied. The adsorption capacity was determined, the constants of chromium(VI) adsorption on iron(III) oxide for the pseudo-second-order model were calculated, and the diffusion coefficients for the process were evaluated. Original Russian Text ? V.N. Belyakov, T.V. Yatsenko, T.V. Mal’tseva, A.V. Pal’chik, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 5, pp. 753–756.     

The standard enthalpies of formation of 1-nitrodispiro[2.0.2.1]heptane and 1-nitrodispiro[2.0.3.1]octane

The energies of combustion and standard enthalpies of formation of 1-nitrodispiro[2.0.2.1]heptane and 1-nitrodispiro[2.0.3.1]octane were determined experimentally. Original Russian Text ? S.V. Mel’khanova, S.M. Pimenova, N.V. Yashin, 2009, published in Zhurnal Fizicheskoi Khimii, 2009, Vol. 83, No. 7, pp. 1396–1398.     

The complex formation properties of 18-crown-6-2-styrylbenzothiazole and the product of its photocyclization

Complex formation of 18-crown-6-2-styrylbenzothiazole and a crown-containing benzothiazolquinoline derivative with alkaline earth metal perchlorates was studied. The structures and stability constants of the complexes were determined. Original Russian Text ? O.A. Fedorova, E.N. Gulakova, I.E. Lobazova, Yu.V. Fedorov, N.E. Shepel’, L.G. Kuz’mina, 2009, published in Zhurnal Fizicheskoi Khimii, 2009, Vol. 83, No. 6, pp. 1178–1182.     

Gelatin-containing calcium hydroxyapatites: Synthesis and physicochemical characterization

The CaCl₂-(NH₄-)₂HPO₄-NH₃-H₂O-gelatin system was studied at 25°C using the solubility (residual concentrations) method. Stoichiometric nanocrystalline (11–15.4 nm) gelatin-containing calcium hydroxyapatites (HAs) were found to form. They were characterized by chemical analysis, thermal analysis, Xray powder diffraction, and IR spectroscopy. Original Russian Text ? Zh.A. Ezhova, N.A. Zakharov, E.M. Koval’, V.T. Kalinnikov, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 3, pp. 526–530.     

The electrical conductivity of poly-p-xylylene + CdS nanocomposites

The dependence of electrical conductivity on the concentration of CdS (c) and temperature (T) over the temperature range 10–300 K was studied for poly-p-xylylene-CdS (PPX + CdS) nanocomposites prepared by solid-state cryochemical synthesis. The results were discussed in terms of the heterogeneous conductivity model including various charge transfer mechanisms in various nanocomposite regions. Under the illumination of a film with c > 11 vol % by a daylight lamp, the conductivity increased, and the σ(T) dependence was metallic in character at low temperatures. The photoconductivity of films at larger concentrations c was caused by the appearance of photoexcited electrons in CdS nanoparticles, the separation of charges at the nanoparticle-matrix boundary, and percolation effects in films. The PPX matrix was shown to actively participate in electrical conductivity; electrons in this matrix jumped between phenyl rings. The experimental dependence of dark conductivity σ(T) at temperatures from 150 to 300 K was analyzed using the Mott hopping conductivity model with variable jump lengths. The main points of the Mott theory of hopping conductivity were discussed. Original Russian Text ? I.A. Misurkin, S.V. Titov, T.S. Zhuravleva, I.V. Klimenko, S.A. Zav’yalov, E.I. Grigor’ev, S.N. Chvalun, 2009, published in Zhurnal Fizicheskoi Khimii, 2009, Vol. 83, No. 3, pp. 534–540.     

Laser-induced modification of collagen in nucleus pulpose gel

The thermal behavior of collagen in intact and IR laser irradiated nucleus pulpose tissues was studied. The enthalpy of denaturation of the intact tissue was determined (53.1 ± 1.2 J/g of collagen). The denaturation of collagen during laser heating at temperatures below the characteristic melting point occurred under the influence of the photomechanical component of laser irradiation. Original Russian Text ? I.V. Andreeva, N.Yu. Ignat’eva, O.L. Zakharkina, V.V. Lunin, 2009, published in Zhurnal Fizicheskoi Khimii, 2009, Vol. 83, No. 3, pp. 590–592.     

The effect of uniaxial tension on the stability of collagen fibers under the conditions of nonuniform laser heating

Collagen degradation caused by IR laser irradiation in ligament tissues was studied by thermal analysis and cross-polarization optical coherent tomography. It was found that, at 60°C, laser-induced modification of the quasi-crystalline packing of ordered collagen fibers occurred without the helix-coil molecular conformation transition. It was shown that, for uniaxial tension of ligaments, laser irradiation caused serious distortions in the structure of collagen and increased the fraction of macromolecules in the random coil state. It was assumed that the thermomechanical effect of laser treatment during laser heating played an important role. Original Russian Text ? O.L. Zakharkina, N.Yu. Ignat’eva, R.R. Iksanov, V.A. Kamenskii, E.N. Sobol’, V.V. Lunin, 2009, published in Zhurnal Fizicheskoi Khimii, 2009, Vol. 83, No. 2, pp. 383–390.     

Thermal decomposition of some linear trinuclear schiff base complexes with acetate bridges

Ni(II)–M(II)–Ni(II) nuclear structured complexes were prepared from N,N’-bis(salicylidene)-1,3-propanediamine (LH2) and its derivatives N,N’-bis(salicylidene)-2,2’-dimethyl-1,3-propanediamine (LDMH₂) and N,N’-bis(salicylidene)-2-hydroxy-1,3-propanediamine (LOH3), where M represents one of the following metal ions; Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II). Two different μ-bridges are found between the metal nucleus of the complexes. The phenolic oxygens and acetate ions tend to form μ-bridges between the terminal Ni(II) ions and central metal(II) ion. The coordinatively bonded DMF molecules, in the complexes, were observed to abandon the structure between 160–180°C. Further heating resulted primarily in the thermal decomposition of the complexes above 310°C, whereas metal oxide residue mixtures were observed above 650°C.     

Reentrant behavior of poly(vinyl alcohol)–borax semidilute aqueous solutions

 The reentrant behavior of Poly(vinyl alcohol) (PVA)–borax aqueous semidilute solutions with a PVA concentration of 20 g/l and borax concentrations varies from 0.0 to 0.20 M was investigated using dynamic light scattering (DLS) and dynamic viscoelastic measurements. Two (fast and slow modes) and three (fast, middle, and slow) relaxation modes of PVA semidilute aqueous solutions without and with the presence of borax, respectively, were observed from DLS measurements. The fast and middle relaxation modes were q ²-dependent (q is the scattering vector) characteristic of diffusive behavior; however, the slow modes were q ³-dependent, characteristic of intraparticle dynamics. The experimental results showed that the slow relaxation mode dominates the DLS relaxation. The DLS slow mode relaxation time, τ_s, and the viscoelastic modulus G′(ω) and G′′(ω) data had a similar trend and demonstrated reentrant behavior as the borax concentration was increased from 0.0 to 0.20 M, i.e. τ_s, G′(ω), and G′′(ω) fluctuated with increasing borax concentration. The excluded-volume effect of polymers, charge repulsion among borate ions bound on PVA molecules, and intermolecular cross-linking didiol–borate complexation caused an expansion of the polymer chain; however, the screening effect of free Na⁺ ions on the negative charge of the borate ions bound on PVA and intramolecular cross-linking didiol–borate complexation led to a shrinkage of the polymer chain. The reentrant behavior was the consequence of the balance between expansion and shrinkage of the PVA–borate complex. Received: 26 March 1999/Accepted in revised form: 3 September 1999     

Comparative evaluation of magnetite dissolution efficiencies of EDTA and OEDP aqueous solutions

The influence of EDTA and OEDP on the magnetite dissolution rate in various experimental conditions was studied. From a comparative analysis of rate data in commensurate conditions, EDTA is a more efficient complexone than OEDP. The effect of both the nitrogen-bearing and the phosphorus-bearing complexones was to change the potential at the oxide/solution interface. The potential-controlling reaction was recognized as Fe^IIIY⁻ + H⁺ + e = Fe^IIHY⁻. Original Russian Text ? I.G. Gorichev, I.V. Artamonova, E.E. Nifant’ev, E.O. Zaben’kina, V.V. Kurilkin, N.A. Kishkina, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 5, pp. 869–880.     

Exploring the structural,electronic and optical properties of furan-2-carboxaldehyde and 2-acetylthiophene nicotinoylhydrazone

The crystal and molecular structures of nicotinohydrazide-derived hydrazones, N′-(2-furfurylidene)pyridine-3-carbohydrazide and N′-(1-(2-thienyl)ethylidene)pyridine-3-carbohydrazide, have been determined. The compounds have been also characterized by the solid state IR and UV–Vis spectroscopy. The hydrazones exist in the keto-amine form. According to the results of molecules quantum–mechanical calculations, performed for isolated molecules, this tautomeric form is energetically unfavorable but in the solid and solution states the observed intermolecular interactions support the presence of this form. The furan derivative crystallizes in two polymorphic forms with two molecules in an asymmetric unit regardless of the crystallization method.     

Crystal structure of (5-methylcyclopentadienyl)-(1,5-cyclooctadiene) iridium(I)

XRD is used to determine the structure of Cp′Ir(cod) at a temperature of 150(2) K. Crystallographic data for C₁₄H₁₉Ir are: a = 10.8272(5) ?, b = 9.7746(4) ?, c = 10.9180(5) ?, β = 97.3310(10)°, monoclinic symmetry, space group P2₁/n, V = 1146.02(9) ?³, Z = 4, d _calc= 2.199 g/cm³, R = 0.0246. The structure is molecular, built of neutral molecules. The metal atom coordinates carbon atoms of two cyclic ligands: 5-methylcyclopentadienyl-ion (Cp′) and 1,5-cyclooctadiene (cod). Five Ir-C_Cp′ distances lie in the range of 2.21–2.28 ?; four Ir-C_cod distances differ insignificantly, and their average value is 2.114(13) ?. The C₁₁C₁₂C₁₃C₁₄C₁₅ and C₁C₂C₅C₆ planes of ligand fragments are almost parallel, and the angle between normals is 1.9°. In the crystal, molecules are bonded only by van der Waals interactions; in the structure, the eight shortest Ir...Ir distances are in the range of 5.608–7.257 ?. Original Russian Text Copyright ? 2009 by K. V. Zherikova, N. B. Morozova, and I. A. Baidina __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 3, pp. 591–594, May–June, 2009.     

Extraction-photometric determination of <Emphasis Type="Italic">N</Emphasis>′,<Emphasis Type="Italic">N</Emphasis>′-dialkylbenzhydrazides as its complexes with copper

A procedure for extraction-photometric determination of N′,N′-dialkylbenzhydrazides has been proposed; the procedure is based on the formation of its colored complex with copper (II) followed by extraction with p-xylene and absorbance measurements at 460 nm (0.1–0.4 mmol of analyte in the sample) or at 330 nm (0.005–0.025 mmol of analyte in the sample).