Synthesis and photo- and electroluminescent properties of copolyfluorenes with nile red fragments in side chains

New copolyfluorenes containing units of 4,7-dibromo-2,1,3-benzothiadiazole (green luminophore) and 3,6- or 2,7-dibromocarbazole derivatives with side-chain fragments of green (4-pyrrolidinyl-1,8-naphthalimide) and red (Nile red) luminophores and additional carbazole or diphenyloxadiazole groups are synthesized via the Suzuki copolycondensation reaction. The structure of the polymers is modified via insertion of triphenylamine, aryloxadiazole, and quinoxaline units in the backbone of copolyfluorenes and via introduction of triphenylamine, fluorene, and benzene terminal groups. The molecular-weight characteristics of the polycondensation products and the specific features of the transfer of polyfluorene emission energy to the indicated luminophores in solutions and films are studied. Coating the emissive copolyfluorene layer with electron-conducting and hole-blocking layers of poly[9,9-bis(6′-diethoxyphosphorylhexyl)fluorene] makes it possible to increase the brightness of light-emitting diodes (to 2380–3900 cd/m²) and their current and luminance efficiencies.     

Polyfluorobenzoyl chlorides and isothiocyanates in reactions with CH-reactive benzimidazoles

Reactions of 2-benzoylmethylbenzimidazole with tetra- and pentafluorobenzoyl chlorides afford fluorine-containing 6-benzoyl-7H-benzimidazo[3,2-a]quinolones. 2-Cyanomethyl- or 2-benzoylmethylbenzimidazole reacts with tetra(penta) fluorobenzoyl isothiocyanates to give fluorine containing 1,3-benzothiazinones, which differently behave in reactions with cycloalkylimines.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 720–724, March, 2005.     

Weakening of amide conjugation with a nitrogen atom included in a four-membered ring

The barriers to amide rotation about the N-N bond in 1-nitrosoazetidine, dimethylnitrosamine, 1-formylazetidine, 1,1-carbonylbisazetidine, 1-dimethylcarbamoylazetidine, and dimethylformamide were measured by dynamic NMR spectroscopy. 1,1-Carbonylbisazetidine and 1-dimethylcarbamoylazetidine, the structures of which were confirmed by data from the PMR and ¹³C NMR spectra, were obtained.Translated from Khimiya Geterotsiklicheskikh Soedenenii, No. 7, pp. 912–194, July, 1987.     

Synthesis of 1-aryl-3a,8b-dihydroxy-3-(1-hydroxyethylidene)-1,3,3а,8b-tetrahydroindeno[1,2-<Emphasis Type="Italic">b</Emphasis>]pyrrole-2,4-diones

Reaction of acetoacetic acid N-arylamides with ninhydrin at boiling in ethanol in the presence of iron(III) chloride afforded 1-aryl-3a,8b-dihydroxy-3-(1-hydroxyethylidene)-1,3,3а,8b-tetrahydroindeno[1,2-b]-pyrrole-2,4-diones. The structure of compounds was confirmed by IR, ¹Н NMR, and mass spectra and X-ray diffraction (XRD) analysis.     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-and <Emphasis Type="Italic">C</Emphasis>-trimethylsilyl-substituded anililes

N-Metallation of bromoanilines with ethylmagnesium bromide followed by a reaction with trimethylchlorosilane provided N-mono and N-bis(trimethylsilyl)bromoanilines depending on the structure of substrate. The metallation of bissilylated bromoanilines with butyllithium permitted the introduction of a trimethylsilyl substituent in the aromatic ring. Previously unknown 2-bromo-N,N-bis(trimethylsilyl)aniline, 2,6-dibromo-N-trimethylsilylaniline, 2,6-dibromo-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilylaniline, 2-bromo-6-trimethylsilyl-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilyl-N-trimethylsilylaniline, 2,4,6-tribromo-N-trimethylsilylaniline, and 2,4,6-tribromo-N,N-bis(trimethylsilyl)aniline were prepared. The structures of the compounds obtained were established by the chromato-mass spectrometry and ¹H, ¹³C, and ²⁹Si NMR spectroscopy.     

Fluorine-containing heterocycles: XVII. (Tetrafluorobrnzoyl)thioureas in the synthesis of fluorine-containing azaheterocycles

Proceeding from (tetrafluorobenzoyl)thioureas fluorine-containing derivatives were synthesized of 1-aryl-2-ethylthioquinazolin-4-one, [1,3]benzothiazin-4-one, and also of thiazolidine and 1H-1,2,4-triazole.     

Synthesis of N-substituted 7-aryl-5-methyl-4,7-dihydrotetrazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidine-6-carboxamides

Three-component reaction of N-methyl- or N,N-diethyl-3-oxobutanamide with aromatic aldehydes and tetrazol-5-amine monohydrate gave the corresponding N-substituted 7-aryl-5-methyl-4,7-dihydrotetrazolo-[1,5-a]pyrimidine-6-carboxamides.     

The stability of a flow in a side-heated vertical layer with internal heat sources

The linear stability of a combined convective flow in a side-heated plane vertical layer of incompressible fluid is considered. The layer contains uniformly distributed heat sources. The steadystate flow is a superposition of the Gershuni convective flow and a flow induced by the action of the internal heat sources. The stability maps of the combined flow are constructed for different values of the Prandtl number. It is found that the internal sources damp the action of the mechanisms of the Gershuni flow crisis. The lateral heating may result in both the stabilization and the destabilization of the flow caused by the action of internal heat sources.     

Synthesis and Biological Activity of 4,5,6,7-Tetrahydro-2H-indazole Derivatives

Russian Journal of General Chemistry - Novel 4,5,6,7-tetrahydro-2H-indazole derivatives were obtained via the reaction of N1,N3,2-triaryl-6-hydroxy-6-methyl-4-oxocyclohexane-1,3-dicarboxamides with...     

Compact Energy Storage Device for Electromagnetic Launchers of Solids

Numerical study has been performed to investigate the operating characteristics and modes of an energy storage device based on a pulsed magnetohydrodynamic generator and a step-up transformer with a stored energy of 25 and 50 MJ and a secondary winding current of 250 kA at the final stage of operation. The operating parameters of such storage devices with rail launchers operating in the mode of rapid-fire launching of several projectiles were calculated.