Conjugation effects and optical spectra of 1,2-diphosphole cycloadducts

Russian Chemical Bulletin - Quantum chemical calculations and a comparative analysis of Raman spectra of 3,4,5-triphenyl-1-propyl-1,2-diphosphole (1),...     

Diels-alder reaction of 1-methylcycloprop-2-ene-1-carbonitrile with methyl 2-oxo-2H-pyran-5-carboxylate

The Diels-Alder reaction of 1-methylcycloprop-2-ene-1-carbonitrile and coumalic acid methyl ester (methyl 2-oxo-2H-pyran-5-carboxylate) gave a 2:1 adduct with endo-syn configuration of both cyclopropane fragments, which was established by X-ray analysis. According to the ¹H NMR data, the reaction involves intermediate formation of decarboxylated 1:1 adduct having a cycloheptatriene structure; its isomerization into the corresponding caradiene, followed by addition of the second dienophile molecule, was confirmed by quantum-chemical calculations.     

Alkali metal polyphosphides as intermediates in the synthesis of organophosphorus compounds from elemental phosphorus

Russian Chemical Bulletin - Methods for the preparation of alkali metal polyphosphides, as well as their reactivity with respect to organic substrates, namely, electrophilic reagents and...     

Versatile Cycloaddition Reactions of 1-Alkyl-1,2-Diphospholes

Abstract

The reactivity of 1-alkyl-1,2-diphospholes in cycloaddition reactions with dienes, dienophiles or 1,3-dipoles was examined. 1-Alkyl-1,2-diphospholes (2 ) exhibit dual reactivity and act as diene toward maleic acid derivatives or as dienophiles with 2,3-dimethyl-1,3-butadiene. The 1-alkenyl-1,2-diphospholes (4 ) are readily involved in intramolecular [4 + 2] cycloaddition reactions leading to cage phosphines (5 ). Interaction of 1-alkyl-1,2-diphospholes (2) with 1,3-dipolar reagents (diphenyldiazomethane and nitrones) results in formation of the bicyclic phosphiranes (8) and dimers of 1-alkyl-1,2-diphosphole oxides (9) or bicyclic phosphine oxides (10) with a β-lactam moiety depending on temperature.     

Reactions of sodium 3,4,5-triphenyl-1,2-diphosphacyclopentadienide with alkyl halides and silicon and tin chlorides

Reactions of sodium 3,4,5-triphenyl-1,2-diphosphacyclopentadienide with primary alkyl bromides, secondary alkyl iodides, and silicon and tin chlorides gave stable 1-substituted 1,2-diphospholes. In a solution of 3,4,5-triphenyl-1-trimethylstannyl-1,2-diphosphacyclopenta-2,4-diene, the Me3Sn group migrates between two phosphorus atoms.     

Use of organosilicon compounds as modifiers of epoxy compositions

Organosilicon compounds used to improve the strength and adhesion properties, as well as the thermal stability, of epoxy compositions are reviewed. Properties of composition on the basis of bisphenol A-based ED-20 resin cured with a KrOOT-1 silicon-containing amine are described.     

Synthesis of alkali and heavy metal dithio- and thiocarbamates based on N-(Β-aminoethyl)piperazine

A series of alkali and heavy metal dithio- and thiocarbamates based on N-(-aminoethyl)piperazine and its derivatives N-(-piperazinoethyl)imides, N-[(-2,5-dimethyl-1-pyrrolyl)ethyl]piperazine, and N-(-salicylideneaminoethyl)-piperazine is prepared. Methods for preparation of dithio- and thiocarbamates based on piperazine are improved. Alkali metal dithio- and thiocarbamates based on piperazines form polymeric complexes with heavy metals.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1524–1528, November, 1989.     

Diagnostics of an O<Subscript>2</Subscript>(<Superscript>1</Superscript>Δ) generator using multichannel recording of oxygen emission spectra

The concentrations of water vapor and O₂(¹Δ), as well as the temperature in the gas flow at the exit of a singlet oxygen generator, are determined using multichannel recording of the singlet oxygen emission spectrum in the bands at 634, 703, 762, and 1268 nm. The water vapor concentration is found from the intensity ratio of the 762-nm band, which corresponds to the ¹Σ → ³Σ transition of the oxygen molecule, and the dimole emission band at 634 nm. From the ratio of the integrated intensities of the bands at 634 and 1268 nm, the O₂(¹Δ) concentration is determined and it is shown that the yield of O₂(¹Δ) at the exit from the gas generator is about 52%. The temperature of the gas flow, determined by the rotational structure of the oxygen emission spectrum in the band at 762 nm, is about 300 K under the nominal conditions of the gas generator operation. The ratio of the photon fluxes in the 703 and 634nm bands of the O₂(¹Δ) dimole emission is 1.06. The temperature dependence of the dimole emission bandwidths is determined, which can be used for estimating the gas temperature at the exit of the O₂(¹Δ) generator.     

Synthesis and photophysical properties of 2,3,4,5-tetraphenyl-1-n-octyl-1-monophosphole

Russian Chemical Bulletin - A new method for the preparation of 2,3,4,5-tetraphenyl-1-octyl-1-monophosphole was developed. It was shown that the reaction of n-octyl chloride with a mixture of...