On the photonics of aromatic azide molecules

Energies of electronically excited states of a number of aromatic azides have been calculated using ab initio quantum-chemical methods. It has been shown that the relative arrangement of the singlet and triplet states of the A′ and A″ types changes with an increase in the number of π electrons in the system. As in the case of other classes of heteroaromatic molecules, five relative locations of these states are possible. On this basis, the dependence of the luminescent and photochemical properties of molecules of aromatic azides on their chemical structure has been rationalized.     

The role of the medium in electrochemical functionalization and dispersion of carbon nanotubes

An electrochemical method for dispersion of single-walled carbon nanotubes (SWNTs) is described. The technique is based on grafting of oxygen-containing functional groups to the nanotube surface during electrolysis in aqueous and nonaqueous potassium bromide solutions. A dependence of the degree of functionalization of nanotubes on the solvent was revealed experimentally. Nanotubes treated in DMSO have about 14 carbon atoms per oxygen atom from functional groups (cf. nearly four C atoms per oxygen atom in the nanotubes treated in aqueous solutions). The corresponding maximum specific capacities of the electrodes are nearly 10 and 60 F g⁻¹. The samples treated in solutions of KBr in DMSO have about 300 carbon atoms per bromine atom on the nanotube surface (cf. only 30 carbon atoms in the samples treated in aqueous solution). A mechanism of electrochemical modification of SWNTs is proposed. Its key step is production of atomic oxygen that oxidizes the nanotube surface with the formation of functional groups.     

Photochromic fulgimide-containing silicones immobilized on the surface of polyarylate

Photochromic coatings immobilized on the surface of polyarylate films are prepared on the basis of fulgimides, oligosiloxanes, and oligosilazanes. The irradiation of coatings with UV light at a wavelength of @380 nm and visible light at a wavelength above 500 nm results in photoinduced reversible transitions between open and colored cyclic forms. Photochromic polymer films with the most acceptable characteristics are obtained from fulgimide-containing oligoaminosiloxane and oligovinyldimethylsilazane. It is found that the photosensitivity of these films is higher than that of similar films based on 1,2-dihetarylethenes.     

Critical Dynamics of the Phase Transition to the Superfluid State

Theoretical and Mathematical Physics - In papers devoted to superfluidity, the generally accepted statement that the dynamics of the corresponding phase transition is described by the stochastic...     

Liquid-Vapor Phase Equilibria in Binary and Ternary Subsystems Constituted by Pyrocondensate Components from the Pyrolysis of Straight-Run Naphtha

Liquid-vapor equilibrium in the binary subsystems of the ethylbenzene-o-xylene-α-methylstyrene-p-vinyltoluene-dicyclopentadiene-indene system was predicted using UNIFAC group model and studied experimentally. To assess the reliability of parameters, the liquid-vapor equilibrium was studied experimentally in the ternary systems and compared with the calculated data.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 3, 2005, pp. 403–407.Original Russian Text Copyright © 2005 by Prikhod’ko, Komarova, Gorelova, Gorlova, Bondaletov.     

Synthesis and properties of copoly(arylene ether ketones) with side reactive groups

A number of amorphous copoly(arylene ether ketones) with side reactive groups (carboxyl and phthalimidine) have been synthesized via the nucleophilic substitution of a halogen atom in activated aryl halide. The said copolymers exhibit an increased onset temperature of softening (170–250°C) and good mechanical characteristics: in the case of films, the breaking strength is 88.5–119 MPa, while for plastics, the notched specific impact strength varies from 16 to 22 kJ/m² and the bending strength is in the range of 135–217 MPa.     

Reaction of methyl propiolate with thiosemicarbazones

Methyl propiolate reacts with thiosemicarbazones in methanol in the presence of triethylamine to give 2-benzylidene(thenylidene, or furfurlidene)azino-3H-1,3-thiazin-4-ones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 123–125, January, 1988.     

Ring-chain tautomerism of spiro amino ketal alkaloids

Summary Under the action of acids, the spiro amino ketal grouping of hypecorine opens. The structure of the pseudohypecorine chloride so formed has been confirmed by spectroscopy and by its reduction to the corresponding dihydro derivative. When the latter was treated with boiling acetic anhydride, the tetrahydroisoquinoline nucleus opened and a 0,N-diacetyl derivative was formed.All-Union Scientific-Research Institute of Medicinal Plants, Moscow. Leningrad Institute of Pharmaceutical Chemistry. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 491–495, July–August, 1976.