Binulcear polyunsaturated organosilicon dendrimers

Binuclear polyunsaturated organosilicon dendrimers of the zero and first generations, whose central silicon atoms are linked by-CH₂-Ch₂-,-CH=CH-, or-C≡C-bridges, and also containing internal (C≡C) and (CH=CH) groups are prepared. NMR spectra of all the compounds obtained are studied. Their molecular weights were calculated and evaluated experimentally. Key parameters of new dendrimers are presented.     

Organomagnesium Synthesis of <Emphasis Type="Italic">sec</Emphasis>-Butyl- and <Emphasis Type="Italic">tert</Emphasis>-Alkylchlorogermanes and Their Reaction with Ethynylmagnesium Bromide

The limits of application of organomagnesium synthesis to the substitution of chlorine atoms in tetrachlorogermane with bulky alkyl groups are established. The reaction of tetrachlorogermane with 2-butylmagnesium chloride leads to the substitution of one, two, or three chlorine atoms, yielding the corresponding alkylchlorogermanes (MeEtCH)_nGeCl_4-n . The reaction of GeCl₄ with tert-alkylmagnesium halides leads to the substitution of only one chlorine atom, yielding tert-alkyltrichlorogermanes RMe₂CGeCl₃ (R = Me, Et, Bu). tert-Butyltrichlorogermane reacts with ethylmagnesium bromide to give ethyl(tert-butyl)dichlorogermane. Isopropyltrichlorogermane reacts with tert-butylmagnesium chloride to give isopropyl(tert-butyl)dichlorogermane. This shows that the organomagnesium synthesis does allow linking of two bulky substituents to the germanium atom. The reaction of tert-alkyltrichlorogermanes and 2-butyltrichlorogermane in THF with ethynylmagnesium bromide, in which the hydrocarbon group is the most sterically accessible, allows substitution of all the three chlorine atoms, yielding the corresponding alkyl(triethynyl)germanes. The latter compounds react with the Grignard reagent and trimethylchlorosilane to give the corresponding alkyl(trimethylsilylethynyl)germanes.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 5, 2005, pp. 757–761.Original Russian Text Copyright © 2005 by O. Yarosh, Voronkov, Zhilitskaya, N. Yarosh, Albanov, Korotaeva.     

Novel acyclic and macrocyclic highly unsaturated silahydrocarbons

Two novel silicon-containing acetylenic synthons, 1-[dimethyl(ethynyl)silyl]-2-[ethynyl(methyl)-(vinyl)silyl]ethyne and bis[(ethynyldimethylsilyl)ethynyl](methyl)vinylsilane, were obtained by the reaction of diethynyl(methyl)vinylsilane with ethylmagnesium bromide and ethynylfluorodimethylsilane. The reaction of magnesium derivatives of the products and diethynyl(methyl)vinylsilane with organylhalosilanes gave macrocyclic polyunsaturated silahydrocarbons containing numerous endo- and exocyclic miltiple bonds.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 10, 2004, pp. 1612–1616.Original Russian Text Copyright © 2004 by O. Yarosh, Zhilitskaya, N. Yarosh, Istomina, Albanov, Chuvashev, Voronkov.This revised version was published online in April 2005 with a corrected cover date.     

Synthesis of Salts and Ionic Liquids on the Basis of 2-Aminothiazolium Cations

Russian Journal of General Chemistry - The base-free reactions of 2-aminothiazole with α-iodoketones were studied. Depending on the reaction conditions, linear or cyclic 2-aminothiazolium...     

New polyunsaturated silahydrocarbons

12-Membered highly unsaturated macrocyclic silahydrocarbon containing exocyclic methyl and benzyl groups is synthesized by the reaction of benzylmethyldi(bromomagnesiumethynyl)silane with dimethyldichlorosilane. Hydrosilylation of benzyl(triethynyl)silane with trichlorosilane with subsequent reaction of the formed adduct with trimethylsilylmagnesium bromide leads to the spherical dendrimer (N_C = 3) containing the benzyl group at the central Si atom, -CH=CH- groups in the inner sphere and numerous triple bonds on periphery. NMR spectra of the obtained compounds were studied.     

Alkylation of 2-methylimidazole with iodomethylsilanes

2-Methyl-1,3-bis[(1-methylsilolan-1-yl)methyl]-1H-imidazolium triiodide, 1,3-bis{[dimethyl-(phenyl)silyl]methyl}-2-methyl-1H-imidazolium iodide and triiodide, and cyclic 3,3,5,5,10-pentamethyl-4-oxa-7-aza-1-azonia-3,5-disilabicyclo[5.2.1]deca-1(10),8-diene iodide were synthesized by solvent-free reactions of 2-methyl-1H-imidazole with 1-(iodomethyl)-1-methylsilolane, (iodomethyl)(dimethyl)phenylsilane, and ethynyl(iodomethyl)(dimethyl)silanes, respectively, in the absence of base catalyst.     

Novel Highly Unsaturated Macrocyclic and Macrobicyclic Silahydrocarbons Containing Si-H Bonds and Exocyclic Vinyl Groups

The first representative of cycloorganylhydrosilalkynes (C≡CSiHR)_n, tetramethylcyclotetrasilethyne, was prepared by organomagnesium synthesis. The same procedure was used to synthesize 15-membered polyunsaturated silahydrocarbons containing both triple and double bonds in the ring and an exocyclic vinyl group. Organomagnesium synthesis was also used for preparing previously unknown polyunsaturated macrobicyclic silahydrocarbons containing a -CH₂CH₂- bridge. The ¹H, ¹³C, and ²⁹Si NMR and IR spectra of the synthesized compounds were studied.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 7, 2005, pp. 1157–1160.Original Russian Text Copyright © 2005 by O. Yarosh, Zhilitskaya, Istomina, N. Yarosh, Albanov, Voronkov.