Formation of poly-p-phenylene thin films and their composites with fullerene by discrete evaporation in vacuum

The effect of parameters of discrete evaporation of poly-p-phenylene (PPP) and C₆₀ on quality of the films formed was studied, PPP and PPP/C₆₀ composite films and heterostructures based on these materials were prepared. It was established that the conjugation length of PPP macromolecules consists of –9–10 units, and they can be electrochemically transformed into the radical cation state at a potential of 2.10 V. Glassy carbon-PPP-C₆₀-Al heterostructures with a rectification ratio of 10⁶–10⁸ were formed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No, 12, pp, 2918–2921, December, 1996.     

Mechanism of SO2 adsorption on receptor sites incorporated into porous SiO2 films

SO₂ adsorption on porous SiO₂ films containing alkylamine sites is considered. Alkylamine-SO₂ complexes are modeled using the molecular mechanics method; it is demonstrated that the SO₂ molecule is adsorbed on the amine-containing group of alkylamine. On the basis of these computations, the alkylamine fragment responsible for SO₂ adsorption was determined, and quantum chemical calculations of the electronic structure and complexation energies depending on the number of ethyl substituents in the alkylamine were performed. The dipole moment of the alkylamine-SO₂ complex is shown to differ strongly in its magnitude from the geometric sum of dipole moments of component molecules. The reasons for the difference are charge transfer to SO₂ and charge redistribution in the alkylamine with decreasing electron density on hydrogen atoms.Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 6, pp. 131–134, November–December, 1993.Translated by L. Chernomorskaya     

First example of the formation of highly ordered supermolecular structures in a series of gibberellin derivatives

The 3-O-palmitate and 3-O-tridecanoate of gibberellin A₃ have been synthesized and monomolecular Langmuir-Blodgett films have been obtained from them.Novosibirsk Institute of Organic Chemistry, Siberian Division of the Russian Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 793–795, November–December, 1994.     

Structure of the dimethylsulfoxide molecule in neutral,acid, and alkaline media

The quantum-chemical SCF LCAO-MO calculations have been carried out in the MNDO/H approximation for the dimethylsulfoxide (DMSO) molecule, its anion [CH ₃ CH ₂ SO]^–, and DMSO adducts with HCL, OH^–, and H₂O. Bond lengths, interbond angles, effective charges on atoms, bond orders, ionization potentials, formation enthalpies, and dipole moments have been calculated. The comparative analysis of quantum-chemical and structural data of the compounds has been carried out.Baikov Institute of Metallurgy, Russian Academy of Sciences. Moscow Mendeleev Chemical Engineering Institute. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 3, pp. 31–35, May–June 1993.Translated by L. Smolina     

Stability of Wetting Films of F108 Triblock Copolymer Aqueous Solutions on Quartz

Wetting films of nonionic F108 triblock copolymer aqueous solutions with concentrations below the CMC containing an electrolyte (NaCl) and formed on a quartz substrate are studied. Primary thick films are disclosed to be metastable. Their temporal stability is explained by the electrostatic repulsive forces. Film thinning and transition to a stable state occur slowly at low electrolyte concentrations (C _NaCl = 10^–5 and 10^–3 M, respectively) and instantly at its high concentrations (C _NaCl = 10^–2 and 10^–1 M, respectively). The stability of thin films is explained by the steric repulsive forces.     

Luminescence-spectral characteristics and conformational transformations in the electronically excited state of the dimethylaminophenyl derivatives of pyridine and pyridinium and pyrylium cations

The electronic absorption spectra and luminescence-spectral characteristics of the 4-dimethylaminophenyl derivatives of pyridine and pyridinium and pyrylium cations in solutions and polymeric films were studied. The obtained data make it possible to suppose that conformations with the orthogonal arrangement of the donating and accepting fragments (TICT structure) both in the cations and in the neutral molecules arc formed as a result of structural relaxation in the excited S₁ state.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, 625–630, May, 1992     

Nanolayers of selected porphyrin and phthalocyanine dyes on solid substrates studied by electronic absorption and IR reflection–absorption spectroscopy

Electronic absorption and IR reflection–absorption spectra in non-polarized and in polarized light for lead porphyrin as well as magnesium and lead phthalocyanine dyes when deposited in the form of Langmuir–Blodgett (LB) nanolayers on solid inorganic surfaces (quartz, semiconductor and metal) were measured. Some IR bands of the Langmuir–Blodgett dye layers’ spectra show frequency shifts and changes in the relative intensities as well as in half widths when compared with the vibrational features of powdered dyes dispersed in KBr pellets, which were used as references. The FT-IR spectroscopic examination of the Langmuir–Blodgett layers allowed to estimate electron redistribution at the interface between dye layer and solid substrates. The Langmuir–Blodgett films of different thicknesses (3, 5, 10 layers) were studied at various angles of IR beam incidence and different light polarizations. The most spectacular results were obtained for the grazing incidence (80°) and films of 5 layers for dyes on the Au substrate. The IR spectroscopy was supported with electronic absorption studies (UV–vis) to follow interaction at interface between the dye layers and the substrates as well as to evaluate linear dichroism and to determine arrangement of molecules in the Langmuir–Blodgett films. Molecular arrangement in the Langmuir–Blodgett layers was discussed. It was shown that the dye molecular planes are rather randomly oriented in the Langmuir–Blodgett films with a tendency that the Q_y and Q_x transition moments in the phthalocyanine macroring are slightly directed along the y-axis (Langmuir–Blodgett dipping direction) and the x-axis direction, respectively.     

Carbonylation of acetaldehyde in the presence of transition metal compounds

The carbonylation of acetaldehyde to give butyl lactate has been carried out in the presence of rhodium and cobalt compounds atP _CO=5–9 MPa andT=383–483 K.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 570–571, March, 1995.     

Limits of isomorphous substitution of molecules in normal paraffins as a function of temperature

The limits of isomorphous substitutions and the symmetry of synthetic binary solid solutions of paraffins C_nH_2n+2 with n=17–24 have been studied by X-ray diffraction and thermal X-ray diffraction. Principles of isomorphous substitutions of paraffin molecules are suggested which take into consideration the length (n), the symmetry (parity of n), and the intensity of thermal rotational motion of component molecules.St. Petersburg State University. Translated fromZhurnal Strukturnoi Khimii Vol. 34, No. 4, pp. 117–127, July–August, 1993.Translated by T. Yudanova     

Electrochemical Behavior of Partially-Discharged Li x V2O5 Electrodes upon Interruption of Current

A mathematical diffusion model, which takes into account the electrochemical behavior of partially-discharged thin-layer electrodes made of intercalation materials upon interruption of circuit, is put forward. The applicability of the model is tested by the example of Li _x V₂O₅ films. According to theoretical calculations and experimental data, the equilibrium potential of the films studied depends practically linearly on the degree of intercalation with a slope of –0.8 V for intercalation degrees of 0.3–0.7. The chemical diffusion coefficient of lithium in the films is equal to 1.5 × 10^–11 cm²/s and changes insignificantly at these intercalation degrees.     

Vibronic coupling effects in trimeric mixed-valence clusters

The spectrum of a trimeric mired-valence cluster d₁–d₁–d₂ is calculated in the Piepha-Krausz-Schatz vibronic model. Based on the vibronic spectra obtained magnetic properties of the d₁–d₁–d₂ cluster are investigated It is shown that spin of the system's ground state may change not only as a result of double exchange reduction by vibronic coupling, but also due to a diflerence in the eneqy dependence of the lowest vibronic states on the vibronic coupling constant for diflerent total spin values. Unlike previous studies of vibronic interactions in the d₁–d₁–d₂ cluster, in this study the diagonalizations of the vibronic-coupling and double-exchange matrices are fuljilled simultaneously, using Lanczos' method. Due to this, all types 4 vibronic state mixing by double exchange could be taken into account properly.Moldova State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 5, pp. 20–32, September–October, 1993.Translated by L. Smolina     

Electronic structure of the cubic phase of zirconium dioxide

The band structure of the cubic phase of zirconium dioxide is obtained by employing the LMTO method. Its PV-diagram is calculated to determine the equilibrium lattice constant. The emission Zr L_III-spectrum of this compound is interpreted.Institute of Metallophysics, Ukrainian Academy of Sciences. Kiev Polytechnical Institute. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 5, pp. 57–62, September–October, 1993.Translated by O. Kharlamova     

Calculation of the gas hydrate HS-1 framework structure and its energy estimation

Using the Zimmennan-Pimentel potential, we have calculated the basic atomic coordinates of the unit cell of the gas hydrate HS-lframework. A minimum change in the strain energy of hydrogen bonh U_H fakes place in formation of this framework from ice Ih. The dependence of U_H on the lattice parameters is derived.Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 5, pp. 175–178, September–October, 1993.Translated by T. Yudanova     

“Guest-Host” effect in polymer-dispersed nematic liquid crystals

In this paper we report on a new optoelectronic material representing a polymer-dispersed liquid crystal (PDLC) film. This material exhibits optical response to the applied electrical field and is useful for displays and light gates. The effect of azo and anthraquinone dyes on the optical density of PDLC films has been studied. The proportion of the dye dissolved in an LC cell and the molar absorption coefficients were determined, and the influence of the dyes on the scattering efficiency of PDLC films was calculated.Institute of Theoretical and Applied Mechanics, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 6, pp. 114–117, November–December, 1993.Translated by L. Smolina     

Variations in the electronic absorption spectra of phthalocyanine films on successive treatment with nitrogen dioxide and ammonia

The effect of alternating treatment of films of substituted metal phthaloeyanines with nitrogen dioxide and ammonia on their spectral properties is discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 236–239, January, 1996.     

Synthesis and NMR spectra of the hydroxyundecahydro-closo-dodecaborate [B12H11OH]2− and its acylated derivatives

Tetrabutylammonium hydroxyundecahydro-closo-dodecaborate was obtained in high yield via [B₁₂H₁₁NMP]^–(NMP =N-methylpyrrolidone) by the modified method. [B_i2H₁₁OH]^2– is easily acylated by aromatic acyl chlorides to give novel compounds [B₁₂H₁₁OCOAr]^2– in high yields. All the compounds were characterized by standard and special NMR methods.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 722–725, March, 1996.     

Ultraviolet-Laser-Induced Crystallization of Sol-Gel Derived Inorganic Oxide Films

Structural changes stimulated by ultraviolet (UV) laser irradiations of sol-gel derived inorganic oxide films were investigated. Dried gel films of TiO₂, Nb₂O₅, Ta₂O₅, SrTiO₃ and Pb(Zr _x Ti_1–x )O₃ (PZT) were found to be crystallized by the laser irradiation. On the other hand, the photo-induced change in gel films of BaTiO₃, LiNbO₃ and LiTaO₃ was not observed although the laser beams were absorbed in the films. These sol-gel films were thermally crystallized at almost the same temperature around 600–700°C except TiO₂. Thus, the UV-laser-induced crystallization is not directly ascribed to a simple thermal effect with the irradiation. Photochemical properties of the cations are assumed to be important for the change in sol-gel films.     

Equilibrium acidity of potassium (3)−1,2-dicarbadodecahyronidoundecaborate (−1)

Conclusion The equilibrium acidity of potassium dicarbadodecahydronidoundecaborate(–1) when metalated with fluorenylpotassium and indenylpotassium in 1,2-dimethoxyethane was determined, and was found to have a pK _a value of 21.1–21.5 on the Streitwieser scale.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 471–472, February, 1972.     

Thermal and photostability of 5′,7′-dialkoxy-5,6′-dinitro-1,3,3-trimethylspiro(lndolin-2,2′-[2H]chromenes)

Some photochromic indoline spiropyrans have been synthesized and their thermal and photostability examined in films and in solution. Introduction of the NO₂ group into the indoline moiety of the molecule stabilizes the spiropyran form in solution and in films, but blocking the NO₂ group in the pyran moiety by adjacent alkoxy groups enhances the light stability of the compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1202–1205, September, 1987.