Synthesis and properties of polyoxyarylenesiloxanes

High molecular weight polymers containing oligosiloxanes in the backbone were made by the reaction of aromatic diols with α,ω-diaminosiloxane homologs. The glass transition temperatures dropped by 30–40°C in a homologous series with each siloxane added. The thermal stability also suffered when increasing the number of siloxane groups. The polymers all displayed high % char measurements and one polymer (disiloxane) tested had a V₀ rating by UL-94 testing. The trisiloxane-containing polymer had a high percent elongation at break (>300%). All the polymers tested were fairly susceptible to hydrolysis. © 1994 John Wiley & Sons, Inc.     

Synthesis and properties of cyanopyrroles

A number of cyanopyrroles were synthesized. The nitrile group was created by treatment of pyrrolecarboxylic acids with p-toluenesulfonamide and phosphorus pentachloride. It was found that the pyrrole ring is rapidly N-methylated in the presence of diazomethane when it contains three electron-acceptor substituents.Translated from Khimiya Geterotsiklicheskikh Soedinenii. No. 6, pp. 786–789, June, 1976.     

Synthesis and properties of polyamidines

Polymers with amidine groups  NH CRN in the main chain were prepared by acid catalysed melt polycondensation of 4,4′-diaminodiphenyl methane (DAPM) with various orthoesters. The resulting polyamidines were characterized by ¹H-, ¹³C- and ¹⁵N-NMR spectroscopy, differential scanning calorimetry (DSC), thermogravimetry (TGA) and wide angle x-ray scattering (WAXS) measurements. The properties of the polyamidines are strongly determined by the substituent R on the amidine group. Some peculiarities of the polyformamidine (RH) could be attributed to the conformation of the amidine group. Glass transition temperatures varied from 106 to 161°C depending on the substituent R. All polyamidines possessed good thermal stability up to 370°C and, with exception of the polyformamidine, good solubility in common solvents. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 929–938, 1998     

Synthesis and properties of tetraphenyltriafulvene

The reaction of the 1,2-diphenylcyclo propenium ion (5) with benzhydrylmagnesium bromide exclusively affords 1,2-diphenyl-3-benzhydrylcyclo propene (4), though the reaction of 5 with benzhydryllithium in the presence of lithium chloride yields no cyclopropene 4 but 1,3-diphenyl-3-benzhydryl-cyclopropene (6) via the intermediate formation of 1,2-diphenyl-3-chlorocyclopropene (7). The hydride abstraction from the cyclopropene 4 followed by deprotonation gives tetraphenyltriafulvene (2) as dark red crystals. The ¹³C NMR spectrum, as well as a bathochromic shift of the longest-wavelength absorption in the electronic spectrum with decrease in solvent polarity, indicates a considerable contribution of the dipolar structure at the ground state of 2. The cyclic voltammetry on 2 reveals that 2 can be readily oxidized to a stable cation radical and a less stable dication. The cation radical was also generated by chemical oxidation with silver tetrafluoroborate or antimony pentafluoride, and was investigated by ESR spectroscopy.     

Synthesis and properties of pyridinocalixarenes

Several facets of pyridinocalixarene chemistry have been investigated including reaction pathways for their formation from the base-catalyzed alkylation of the parent calixarenes with PicCl·HCl, effect of the nature and identity of the base on regio- and stereoselectiveO-alkylations, creation of molecular asymmetry in calix[4]arenes and enantiomeric resolution, conformation and conformational mobility, and complexation.This paper is dedicated to the commemorative issue on the 50th anniversary of calixarenes.     

Synthesis and properties of polythienylenes

Although polymerization of 2,5-dibromothiophene via coupling of the Grignard reagent with organonickel salts was reported in two earlier communications, a detailed examination of reaction variables was not done. This report provides results from variation in the following: time, amount of magnesium, amount of iodine, dilution, and variation in the halide of the monomer. The highest yield was obtained for reactions with 1:1 molar ratio of monomer to magnesium in more concentrated solutions of tetrahydrofuran for a reaction time of 4 h. For variation in the halogen of the monomer the following yield sequence was obtained: I > Br > Cl. The results are compared with the corresponding benzenoid system investigated by Yamamoto. In addition, polymerization studies were carried out with other brominated thiophene monomers. Use of an organic promoter (cis-1,4-dichloro-2-butene) in place of a nickel salt proved successful in the generation of poly(2,5-thienylene).     

Synthesis and properties of silacyclobutylsilazanes

Ammonolysis of silacyclobutanes {ie305-01} (R=Cl, CH₃) gives silacyelobutane di- and polysilazanes. Reaction of the disilazane {ie305-02} with 1-chloro-1-methyl-1-silacyelobutane at 20–80° gives a trisilyl-substituted amine {ie305-03}. Trisilyl-substituted amines with one silacyclobutyl group, are obtained by reacting silacyclobutanes {ie305-04} (R=CH₃, C₆H₅). with sodium or potassium silylamides prepared from hexamethyldisilazane. It is shown that it is possible to obtain silylamides by reacting disilazanes directly with potassium metal at 90–100°.     

Synthesis and spectroscopic properties of

The title compound has been synthesized as the first oligothiophenophane that has the typical stacking structure of a layered cyclophane and can behave as an ideal pi-dimer model.     

Synthesis and properties of azidostyrylquinolines

Isomeric azidostyrylquinolines with a 4-azidostyryl group in position 2 or 4 of the quinoline ring have been synthesized. In the neutral form the azidostyrylquinolines absorb in the near UV but the protonated species absorb in the short wavelength region of the visible spectrum. In both forms the azides are lightsensitive and decompose under the influence of light with a quantum yield close to 1. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 555–561, April, 2007.     

Synthesis and properties of B-tri-n-butylmercaptoborazoles

Summary Some B-tri-n-butylmercapto derivatives of borazole were synthesized by the reaction of lead n-butylmercaptide with B-trichloroborazole and its homologs. A study was made of the reactions of the synthesized borazole derivatives with methyl alcohol, amines, and ammonia.     

Synthesis and properties of polyimidazopyrrolones

The preparation of polyimidazopyrrolones by three general synthetic methods has been presented. The effects of structure, conversion temperature, and conversion environment were determined. The polyimidazopyrrolones were shown to retain useful mechanical properties at elevated temperatures, after severe chemical treatment and after unusually high exposure to ionizing radiation. Thermogravimetric analysis of the polymers indicated the effect of structure on oxidative stability was relatively minor; furthermore, the relative stabilities of a series of eight polymers in air were not directly comparable to the order of stability in a vacuum environment.     

Synthesis and absorption-fluorescence properties of

1,4-Bis(²-pyrazolin-3-yl)benzene derivatives were synthesized by the reaction of dibenzal-p-diacetylbenzene or 1,4-bis(-dimethylaminopropionyl)benzene with various hydrazines. Some of these derivatives were converted to the corresponding 1,4-bis(3-pyrazolyl)benzene derivatives by oxidative dehydrogenation with sulfur. The absorption and fluorescence spectra of the synthesized compounds were measured, and the fluorescence quantum yields were determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 79–83, January, 1980.