Morphology and spectral properties of thin films of benzoxazole derivatives of biphenyl

We have studied the spectral properties and morphology of thin films (TVD films) formed by thermal vacuum deposition of 4,4′-bis[(E)-1-(1,3-benzoxazol-2-yl)-2-ethenyl]-1,1′-biphenyl and its substituted derivatives. We have shown that introducing bulky 2,2′-oxyhexyl substituents into the biphenyl units leads to a shift of the fluorescence maximum for the TVD films toward shorter wavelengths, a decrease in their photostability, and aggregation of the films during storage. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 3, pp. 300–303, May–June, 2007.     

Reaction of undecyl radicals with aromatic hydrocarbons

A competition method (R^.+O₂RO ₂ ^. , R^.+XHRH+X^.) is proposed to measure the relative rate constants for the interaction of alkyl radicals with different organic compounds. Partial (per C–H bond) rate constants have been determined for the reaction of undecyl radicals with cumene, ethylbenzene and toluene.

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(R^.+O₂RO ₂ ^. , R^.+XHRH+X^.), . ( C–H ) , .

     

Mono- and multimolecular Langmuir-Blodgett films as protective coatings for friction surfaces

Tribological properties of monomolecular Langmuir-Blodgett films formed from behenic acid, dimethyl octadecylmalonate, 2,4-heneicosanedione, and its copper complex were studied and compared with those of a self-arranged monolayer of octadecyltrichlorosilane. In the micrometer contact range, in friction of a modified silicon surface with a steel ball (indentor), the monomolecular Langmuir-Blodgett films under consideration surpass in the wear resistance the chemisorbed monomolecular octadecyltrichlorosilane film by a factor of 40. The stability of Lamgmuir-Blodgett films in friction correlates with the density of molecular packing on the surface. The friction and wear of Langmuir-Blodgett films are accounted for by the difference in the density of molecular packing of the films under consideration, and also by the transfer of the film substance between the friction surfaces.     

Effect of the medium on the oxidation of aliphatic monocarboxylic acids

Oxidation rates and k₂/k₆ ratios are given for some acids from propionic to lauric. The k₂/k₆ ratio is shown to be influenced by the electrostatic effect of the solvent. A linear dependence between the isodielectric values of k₂/k₆ and the number of methylene groups in the acid molecules is described.

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k₂/k₆ . k₂/k₆ k₂/k₆ .

     

Functionalization of (CdSe)ZnS nanoparticles in reverse micelles of Aerosol OT

A method is optimized for in situ functionalization and activation of (CdSe)ZnS nanoparticles in reverse micelles of Aerosol OT, as well as their conjugation with antibodies. The efficiency of particle functionalization depends on the method of micellar solution formation. Fluorescence remains practically unchanged, provided that NH₂ groups of polymers bonded to the nanoparticles are activated by glutaric aldehyde. All operations of antibody conjugation should be carried out in reverse micelles for the maximum preservation of the fluorescence properties of the particles. Nanoparticles are isolated from reverse micelles using a mixture of acetone with a solution composed of 50 mM NaHCO₃ and 200 mM NaCl. The optimum medium for dissolving the precipitate of the particles consists of NaHCO₃ (50 mM), bovine serum albumin (0.1%), and Twin 85 (0.05%). The modified particles were subjected to photoactivation in an aqueous medium at room temperature and daylight.     

Influence of the conditions of formation of nitrocellulose honeycomb-structure films on their morphology

Physicochemical features of formation and morphology of submicron honeycomb-structure nitrocellulose films with hexagonal cell symmetry were examined.     

Features of the local immobilization of NADPH-cytochrome P450 reductase and cytochrome b<Subscript>5</Subscript> on a solid surface

Using the methods of microcontact printing and atomic force microscopy, we studied a possibility of specific “protein-protein” interactions in the processes of local immobilization of cytochrome b₅ and NADPH-cytochrome P450 reductase on the surface of hydrophilic silicone. It is shown that the formation of protein complexes is possible only at a certain orientation of the molecules defined by the sequence of adsorption of biopolymers.     

Potassium Iodide in Coloring of Polyvinyl Alcohol Film in Oxidizing Solution

Conversion of potassium iodide in polyvinyl alcohol film by its treatment in the (NH₄)₂S₂O₈- CuSO₄-KI-KCl-H₂SO₄-H₂O oxidizing solution, leading to coloring of the film with molecular iodine, was studied. The conversion mechanism was analyzed as influenced by each component of the oxidizing solution.