Ceramic Fe2O3 : Ta Photoelectrodes for Photoelectrochemical Solar Cells

Electrophysical and photoelectrochemical characteristics of Fe₂O₃ photoelectrodes containing various quantities of tantalum are studied. The activation energy for the mobility of charge carriers is determined. An equivalent circuit for the electrochemical cell is constructed by analyzing frequency dependences of real and imaginary components of impedance spectra at different electrode potentials. Parameters of the equivalent circuit elements are calculated and the limiting stage of the electrode process is determined. A photoelectrochemical cell with a system of illuminated n-Fe₂O₃ : Ta– p-Cu₂O photoelectrodes is also studied.     

Reaction of organozine reagents derived from dialkyl 2,2-dibromomalonates and methyl 4,4-dibromo-3-oxoalkanoates with 2-oxochromene-3-carboxamides

Organozinc compounds obtained by treatment of dialkyl 2,2-dibromomalonates with zinc reacted with N-substituted 2-oxochromene-3-carboxamides to give dialkyl 1a-R-carbamoyl-2-oxo-1a,7b-dihydro-2H-cyclopropa[c]chromene-1,1-dicarboxylates or alkyl 2-R-1,3,4-trioxo-2,3-dihydro-1H,9bH-chromeno[3′,4′:1,3]-cyclopropa[1,2-c]pyrrole-9c-carboxylates. Reactions of N-substituted 2-oxochromene-3-carboxamides with zinc enolates derived from methyl 4,4-dibromo-3-oxoalkanoates led to the formation of the corresponding 9c-alkyl-2-R-2,3-dihydrochromeno[3′,4′:1,3]cyclopropa[1,2-c]pyrrole-1,3,4-triones.     

Synthesis of 5,8-Diamino-Substituted Pyrano[4″,3″:4′,5′]pyrido[3′,2′:4,5]thieno[3,2-<Emphasis Type="Italic">d</Emphasis>]pyrimidines and Pyrimido[4′,5′:4,5]thieno[2,3-<Emphasis Type="Italic">c</Emphasis>]isoquinolines

Ethyl 1-amino-8,8-dimethyl-5-(piperidin-1-yl)-8,9-dihydro-6H-pyrano[4,3-d]thieno[2,3-b]pyridine-2-carboxylate and ethyl 1-amino-5-(piperidin-1-yl)-6,7,8,9-tetrahydrothieno[2,3-c]isoquinoline-2-carboxylate reacted with benzoyl isothiocyanate to give the corresponding 1-thioureido derivatives which underwent cyclization to 2,2-dimethyl-5-(piperidin-1-yl)-10-thioxo-1,4,10,11-tetrahydro-2H-pyrano[4″,3″:4′,5′]pyrido-[3′,2′:4,5]thieno[3,2-d]pyrimidin-8(9H)-one and 5-(piperidin-1-yl)-10-thioxo-1,2,3,4,10,11-hexahydropyrimido-[4′,5′:4,5]thieno[2,3-c]isoquinolin-8(9H)-one. The cyclization products were converted into 8-chloro derivatives, and the chlorine atom therein was replaced by various amines.     

Oxidation sequence of sublimedmeso-tetraphenylporphyrinatocobalt(II) films in an atmosphere of nitrogen dioxide

Sublimed films ofmeso-tetraphenylporphyrinatocobalt(II) (CoTPP) undergo a series of chemical transformations in an atmosphere of NO₂. In the first stage, at low NO₂ pressures, the axial five-coordinate Co^IIITPP·NO₂ complex is formed. An increase in the NO₂ pressure and/or exposure results in subsequent oxidation with the formation of a π-radical cation CoTPP^.+. In the latter, according to the IR spectral data, nitrogen dioxide is axially coordinated by the cobalt ion. Further increase in the NO₂ pressure leads to both the formation of a dication and nitration of the porphyrin ring most likely at themeso- and β-pyrrolic positions. Irreversible chemical transformations in the sublimed CoTPP films prevent their use as NO₂ sensors. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 716–719, April, 1998.     

Synthesis of New 1,4-Benzodioxanуl-1,2,4-triazole Derivatives

The reaction of 5-(1,4-benzodioxan-2-yl)-4H-1,2,4-triazole-3-thiol with N-substituted chloroacetic acid amides obtained by condensation of chloroacetyl chloride with various primary amines furnished a series of S-amidomethyl derivatives. The corresponding thiazolotriazolone prepared from 2-[5-(1,4-benzodioxan-2-yl)-4H-1,2,4-triazol-3-ylthio]acetic acid reacted with aromatic aldehydes to form arylidene derivatives.

     

Reaction of the zinc enolate derived from 1,1-dibromo-3,3-dimethylbutan-2-one with 3-aryl-2-cyanopropenoic acid amides and esters and 2-oxochromene-3-carboxamides

Zinc enolate derived from 1,1-dibromo-3,3-dimethylbutan-2-one reacts with 3-aryl-2-cyanoprop-2-enamides and aryl 3-aryl-2-cyanoprop-2-enoates to give the corresponding derivatives of 3-aryl-2-(2,2-dimethylpropanoyl)-1-cyanocyclopropane-1-carboxylic acid as a single stereoisomer with cis arrangement of the hydrogen atoms at the cyclopropane ring. The reactions of the same zinc enolate with 3-morpholinocarbonyl-2H-chromen-2-one and 2-morpholinocarbonyl-3H-benzo[f]chromen-3-one lead to formation of 1-(2,2-dimethylpropanoyl)-1a-morpholinocarbonyl-1a,7b-dihydrocyclopropa[c]chromen-2-one and 1-(2,2-dimethylpropanoyl)-1a-morpholinocarbonyl-1a,9c-dihydrobenzo[f]cyclopropa[c]chromen-2-one, respectively as a single stereoisomer.     

Synthesis and Antibacterial Activity of N-Substituted 2-(Benzylimino)-4-styryl-2,5-dihydrofuran-3-carboxamides

Russian Journal of Organic Chemistry - Previously unknown N-substituted 2-(benzylimino)-4-styryl-2,5-dihydrofuran-3-carboxamides were synthesized by reaction of...     

Synthesis of new heterocyclic systems—substituted spiro[chromene-4,3′-indoles] and spiro[indole-3,4′-quinolines]

Methods have been developed for the synthesis of new heterocyclic systems, spiro[chromene-4,3′- indoles] and spiro[indole-3,4′-quinolines] by the base-catalyzed domino reaction of isatins with 5,5-dimethylcyclohexane- 1,3-dione (or 5,5-dimethyl-3-anilinocyclohex-2-en-1-one) and ethyl cyanoacetate.     

A spectral study of the interaction of dioxygen with sublimed layers of manganese(ii)meso-tetraphenylporphyrinate

The low-temperature interaction of sublimed layers of manganese(ii)meso-tetraphenylporphyrinate (MnTPP) with O₂, which has previously been observed only in solutions and in an inert gas matrix, was found by electron absorption and IR spectroscopy. The coordination of O₂ with sublimed MnTPP layers is only partially reversible. Bands that can serve as IR-spectral markers characteristic of the high-spin Mn^II ion in MnTPP and its axial complexes were observed. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1551–1555, September, 2000.