Rearrangements during nitrosodecarboxylation of isomeric dibromohydroxybenzoic acids

The reaction of 3,5-dibromo-4-hydroxybenzoic acid, its sodium salt, and also sodium 3,5-dibromo-2-hydroxybenzoate with NaNO₂ in a glacial acetic acid at room temperature led to the formation of a mixture of dibromonitrophenol resulting from nitrosodecarboxylation accompanied by a rearrangement processes and followed by oxidation of the arising nitrosophenols.     

Effect of the incomplete accommodation of the heterogeneous recombination energy on heat fluxes to a quartz surface

Taking both the heterogeneous catalytic processes, including the surface formation of particles with excited internal degrees of freedom, and the processes of multicomponent diffusion and heat transfer in the MESOX apparatus fully into account makes it possible to obtain a recombination coefficient and an accommodation coefficient of the oxygen-atoms-on-quartz recombination energy which are in good agreement with the experimental data. The heterogeneous catalysis model constructed can be used effectively for predicting the heat fluxes to the surface of reentry vehicles on their entry into the Earth’s atmosphere.     

Nuclear spin manipulation in interfaces of diluted magnetic semiconductors

Nuclear spin manipulation using an interface of diluted magnetic semiconductors (DMSs) is proposed. On the basis of the first-principles electronic structure calculation, we show that the hyperfine fields at an impurity site in the interface between a DMS and a base substance is dramatically changed by an external electric field. The electric field dependence of the hyperfine fields at the impurity nucleus in the interface of (InMn)As and (GaMn)As is examined.     

Thermoelastoplastic deformation of a thick-walled cylinder with a radial crack

The thermoelastoplastic fracture mechanics problem of a thick-walled cylinder subjected to internal pressure and a nonuniform temperature field is solved by the method of elastic solutions combined with the finite-element method. The correctness of the solution is provided by using the Barenblatt crack model, in which the stress and strain fields are regular. The elastoplastic problem of a cracked cylinder subjected to internal pressure and a nonuniform temperature field are solved. The calculation results are compared with available data. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 3, pp. 173–183, May–June, 2008.     

New sources of “active” halogen bis(dialkylamide)hydrogen dibromobromates, efficient reagents for destruction of ecotoxicants

Bis(dialkylamide)hydrogen dibromobromates were synthesized and their reactivity was investigated in decomposition of diethylphosphonic, diethylphosphoric, and 4-toluenesulfonic acids 4-nitrophenyl esters. The nucleophilic reactivity of a typical α-nucleophile, hypobromite ion, is independent of the source of the active bromine. The cetyltrimethylammonium dibromobromate is a unique reagent for destruction of ecotoxicants. In weakly alkaline media the half-life of 4-nitrophenyl diethylphosphonate did not exceed 6 s at [BrO^?] 0.02 mol l^?1, and the apparent reaction rate compared to water increased ～40-fold. The main factor governing the micellar effects of surfactants is concentrating the substrate in the micellar pseudophase.     

Rare-earth metal 8-hydroxyquinolinate complexes as materials for organic light-emitting diodes

Rare-earth metal 8-hydroxyquinolinates (q) were studied as emission layers for organic light-emitting diodes. Compounds Dyq₃, Tbq₃, and Smq₃ possess weak electroluminescence due to the emission of the ligand, and the electroluminescence of Hoq₃, Tmq₃, and Ybq₃ is due to electronic transitions of the lanthanide ion. The best electroluminescence characteristics were demonstrated by Scq₃ and Yq₃. The power efficiency of the organic light emitter based on ITO/TPD/Scq₃/Yb (ITO is tin-alloyed indium oxide, TPD is N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzidine) is 2.6 lm W⁻¹ at a luminance of the device of 300 cd m⁻².     

Metal complexes of 2-hetarylindandiones-1,3

The chelate and molecular complexes of 2-(2-benzazolyl, perimidyl)-indandiones-1,3 were synthesized for the first time. The structures of the ligands (tautomeric forms) and complex compounds were determined from the X-ray diffraction, ¹H, ¹³C NMR, and IR data and the quantum-chemical calculations (RHF SCF in 6-31 G** basis).