The interactions of (=O→Si)-(benzoyloxymethyl)trifluoro-and -(benzoyloxymethyl) methyldifluorosilanes with a solvent

The IR spectra of solutions of (=OSi)-(benzoyloxymethyl)trifluorosilane (1),-(benzoyloxymethyl)methyldifluorosilane (2), and butyl benzoate (3) are examined in the region of thev(C=O) stretching vibrations in 24 solvents. The ability of compounds1—3 to undergo specific intermolecular interactions is evaluated from the dependence ofv(C=O) on the Kamlet-Taft (^*,, ) parameters, which was obtained for the carbonyl groups involved in the intramolecular coordinate (=OSi) bond and for free carbonyl groups. The corresponding values of the coefficients in the Kamlet-Taft equations are indicative of a weak ability of pentacoordinate silicon compounds1 and2 to undergo acid-base interactions.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 689–692, April, 1995.     

Influence of solvent on ir spectra of aroyl(hydroxymethyl)trifluorosilanes

Conclusions Dipole-dipole interaction of the solvent with molecules of aroyl (hydroxymethyl) trifluorosilanes 4-XC₆H₄COOCH₂SiF₃ is responsible for changes in frequency of the stretching vibrations of groups included in a five-membered ring, containing an intramolecular coordination bond Si 0 (the frequencies C=O and SiF _a , are lowered, and the frequencies _asCOC are raised). The value of the orientation-induction parameter in the Buckingham equation, reflecting the dependence of C=O and SiF _a on the parameters of the medium (, n), increases with increasing electron-donor capability of the substituent X, indicating an increase in the strength of the coordination bond. The coefficient in the Hammett equation is determined by the polar properties of the medium.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2251–2254, October, 1984.     

Li,Cs||F,NO<Subscript>3</Subscript> ternary reciprocal system

The Li, Cs||F, NO₃ ternary reciprocal system was for the first time described and experimentally studied by differential thermal analysis and differential scanning calorimetry. Phase equilibrium states were determined, and so were the compositions and melting points of two ternary eutectics. Reactions describing the chemical interaction in the system were presented.     

Structure of zirconium dioxide based porous glasses

This study is devoted to investigation of the micro- and mesostructure (including fractal properties) of porous zirconia glasses synthesized by precipitation from zirconium n-propoxide solutions in the presence of different hydrolyzing-agent (H₂O) quantities at different temperatures. Analysis of small-angle neutron, ultra-small-angle neutron and X-ray scattering, scanning electron microscopy allows concluding that the synthesized glasses are complex systems with a three-level hierarchical fractal structure. It is revealed that both the temperature of synthesis and the H₂O concentration in the initial solution significantly affect the structural characteristics of the glasses.     

Composition and structure of platinum-containing thin composite films prepared from silica sols

Chemical processes that can occur during aging of sols based on water–alcohol solutions of tetraethoxysilane (TEOS) and hexachloroplatinic acid and during formation of films from these sols are analyzed by the results of visible and UV spectroscopy and X-ray powder diffraction. The sizes and compositions of the platinum particles that are formed in xerogels and in thin films on the nanometer and submicron levels are estimated based on X-ray crystallography, energy dispersive spectral analysis, high-resolution scanning and transmission electron microscopy, and grazing incidence small-angle X-ray scattering studies.     

Chemical interaction in the quaternary mutual systems Li,K‖F,Cl,MoO4 and Li,K‖F(Cl),VO3,MoO4

The Li,K‖Cl,VO₃,MoO₄ system was partitioned into simplexes using graph theory, and the tree of phases for this system was constructed. The equations of the main reactions describing the chemical interaction in the quaternary mutual systems Li,K‖F,Cl,VO₃(MoO₄) and Li,K‖F(Cl),VO₃,MoO₄ were derived using the conversion patterns of partitioning elements. Based on the reaction equations and the data on the boundary elements, the prediction of phases crystallizing in the studied systems was made and confirmed by X-ray powder diffraction analysis.     

Irradiation-induced change of valence of Cr3+ ions doped in alkali sulphates

It is shown by means of investigation of both optical absorption spectra and Roentgen K-lines of chromium doped in LiKSO₄, LiNaSO₄, and Li₂SO₄ · H₂O crystals, that X-irradiation results in change of the impurity charge in a following way: Cr³⁺ + h → Cr⁴, Cr⁴⁺ + h → Cr⁵⁺.     

Nanocomposites Based on Poly(Amide-Imide) Matrix with Na–Mg Triple Chain Hydrosilicate

Crystallography Reports - A new polymer-inorganic nanocomposite composed of fibrous Na–Mg triple chain hydrosilicate with a poly(amide-imide) matrix was developed. Its structure, morphology,...     

Design of Structures of Neutral Nonpolarizing Interference Systems Placed between Media with the Same Refraction Indices

Optics and Spectroscopy - The design of neutral nonpolarizing interference systems formed on the face of one of the two prisms that are components of an optical element in the form of a cube is...     

Morphology and mechanical properties of polymer-inorganic nanocomposite containing triple chain fibrous Na-Mg hydrosilicate

Russian Journal of General Chemistry - A polymer-inorganic nanocomposite of fibrous Na-Mg triple chain hydrosilicate and polyamidoimide based on 4-chloroformyl-(N-p-chloroformylphenyl)phthalimide...