O. G. Yarosh

Highly unsaturated macrocyclic silicohydrocarbons

Abstract Nineteen 12-, 15-, 18-, 24- and 30-membered, highly unsaturated macrocyclic silicohydrocarbons containing -SiCCSi-, (E)-SiCHCHSi- and -SiCH2CH2Si-fragments in the ring were synthesized by the reaction of Me2Si(CCMgBr)2 or BrMgCCMe2SiCCSiMe2CCMgBr with FMe2SiCH2CH2SiMe2F; (E)-FMe2SiCHCHSiMe2F or (E, E)-(ClMe2SiCHCH)2SiMe2; (E)-BrMgCCMe2Si-CHCHSiMe2CCMgBr or Me2Si(CCSiMe2CCMgBr)2 with (E, E)-(ClMe2SiCHCH)2SiMe2; and Me2Si(CCSiMe2CCMgBr)2, BrMgCCMe2-SiCCSiMe2CCSiMe2CCSiMe2CCMgBr or BrMgCCMgBr with (E)-FMe2SiCH  CHSiMe2F under conditions of high dilution. Two 20-membered and one 26-membered macrocyclic silicohydrocarbons containing 6 or 8 silicon atoms bonded by 6 or 8 CC bonds and an endocyclic CH2CH2 or CHCH bridge were obtained for the first time by treating BrMgCCMe2SiCCSiMe2CCMgBr with Cl2MeSiCH2CH2SiMeCl2 or (E)-F2MeSiCHCHSiMeF2, as well as Me2Si(CCSiMe2CCMgBr)2 with (E)-F2MeSiCHCHSiMeF2.

Highly Unsaturated Macrocyclic Organosilicon Compounds

Abstract A series of 12-, 15-, 18-, 21-, 24-, 27- or 30-membered macrocyclic silahydrocarbons of general formula (MeRSiC≡C)n, n=4-10 and R = H, Me, CH2=CH were synthesized by reaction of Me2Si(C≡CMgBr)2, Me(CH2=CH)Si(C≡CMgBr)2, BrMgC≡CMe2SiC≡CSiMe2C≡CMgBr or BrMgC≡CMe,SiC≡CSiMe,C≡CSiMe2C≡CSiMe2C≡CMgBr with MeHSiCl2, Me2SiCl2, Me(CH2=CH)SiCl2 or (ClMe2SiC≡C)2SiMe2. 23-Membered spiromacrocyclic polyacetylenic silahydrocarbons containing 6 silicon atoms, 8 triple bonds and central Si or Ge atoms were prepared by reaction of Me2Si(C≡CSiMe2C≡CMgBr)2 with MC4, (M = Si, Ge).

New polyunsaturated organosilicon dendrimers based on 1,1-diethynyl-and 1-vinyl-1-ethynylsilacycloalkanes

Abstract1,1-Dichloro-and 1-vinyl-1-chlorosilacyclanes were prepared by reactions of tetrachlorosilane or vinyltrichlorosilane with magnesium and 1,4-dibromobutane or 1,5-dibromopentane. The reactions of the products obtained with ethynylmagnesium bromide or bis(bromomagnesio)acetylene yield the corresponding ethynylsilacyclanes. Condensation of 1,1-diethynylsilacyclanes or bis(ethynylsilacyclopentyl)ethyne with an equimolar amount of ethylmagnesium bromide and methylbis(trimethylsilylethynyl)fluorosilane gave the corresponding highly unsaturated mono-and binuclear first-generation dendrimers with the cores formed by the silicon atoms incorporated in silacycloalkane fragments. The 1H, 13C, and 29Si NMR spectra of all the compounds obtained were studied. The key parameters and the chemical graph of the new dendrimers are presented.

1,1-Diethynylsilacycloalkanes and Propellanes Based Thereon

Previously unknown 1,1-diethylnylsilacycloalkanes (CH2)4nSi(C& = CH)2 (n = 3, 4) were prepared by the reaction of HC& = CMgBr with 1,1-dichlorosilacycloalkanes (CH2)4nSiCl2 (n = 3, 4). The reaction of (CH2)4Si(C& = CMgBr)2 with (CH2)4SiCl2 in THF under conditions of high dilution gives cyclo(tetramethylene)- silethynes [(CH2)4SiC& = C]4 with an admixture of cyclodi(tetramethylene)silethyne [(CH2)4SiC& = C]2. The re- action of Me2Si(C& = CSiMe2C& = CMgBr)2 with (CH2)4SiCl2 was used to prepare 1,1,4,4,7,7-hexamethyl-10,10- tetramethylene-1,4,4,10-tetrasilacyclododeca-2,5,8,11-tetrayne.

Spherical polyunsaturated organosilicon and organogermanium first generation dendrimers of regular structure

Synthesis of the mononuclear organosilicon tri-and tetradendrones of the first generation with the repeating CΞC groups as well as the synthones for their construction is carried out. The tetrabranched polyunsaturated dendrimers G1 having regular structure of containing silicon and germanium atoms simultameously are synthesized. The IR and NMR spectra of all the compounds obtained are studied, and molecular masses of the compounds are calculated and evaluated experimentally. Key parameters and chemical graphs of new dendrimers are presented.

Ethynylisopropylgermanes and Their Trimethylsilyl Derivatives

AbstractThe reaction of ethynylmagnesium bromide with chloroisopropylgermanes (i-Pr4-nGeCl/sub> n, n = 1-3) was used to prepare previously unknown ethynylisopropylgermanes i-Pr4-nGe(C≡CH)n (n = 1-3). The reaction of Me3SiC≡CMgBr with i-PrGeCl3 afforded i-Pr(Me3SiC≡C)3-nGeCln (n = 1, 2). The reaction of the monochloride with BrMdC≡CH gave i-Pr(HC≡C)2GeC≡CSiMe3, while with the dichloride, i-Pr(HC≡C)·Ge(C≡SiMe3)2 formed. The latter compounds were obtained by independent synthesis from i-PrGe(C≡CH)3, EtMgBr, and ClSiMe3. The reaction of (bromomagnesioethynyl)triisopropylgermane with Me3SiCl gave i-Pr3GeC≡SiMe3.

High-Temperature Evolution of SiC/C Products Derived from Preceramic Polymers

The products formed during thermolysis of organosilicon polymers containing unsaturated carbon-carbon bonds have been studied within the temperature range 20–1700°C by means of XRD, 13C and 29Si MAS NMR, and Raman spectroscopy. These products are distinguished by their structural instability. A continuous evolution of the products formed during organic–inorganic thermal transformation involves (i) ordering of the local surroundings of silicon atoms, the formation of a silicon carbide crystalline phase, and the transition from β to α and (ii) consumption of carbon for the completion of silicon carbide formation, carbon phase formation, and ordering.

Cyclodimethylsilethenes (Me2SiCHCH)n

Abstract Dodecamethylcyclohexasilethene (Me2SiCHCH)6 (1) was synthesized by autohydrosilylation of HMe2SiCCH in a tetrahydrofuran solution in the presence of H2PtCl6 under high dilution. An analogous reaction of Me2Si(CCH)2 or E-HCCMe2SiCHCHSiMe2CCH with E,E-Me2Si(CHCHSiMe2H)2 gave octamethylcyclotetrasilethene (Me2SiCHCH)4 (2) and decamethylcyclopentasilethene (Me2SiCHCH)5 (3) respectively. The X-ray structure of 3 is presented.

Reaction of di- and trisubstituted ethynylsilanemagnesium halides with dimethylethynylfluorosilane

ConclusionsThe reaction of magnesium bromide derivatives of di- and triethynylsilanes with dimethylethynylfluorosilane gave 1,2-disubstituted silylacetylenes containing ethynyl and vinyl groups at the silicon atoms.

New 15- and 18-membered polyunsaturated macrocyclic silicohydrocarbons

A multistep method is developed for the synthesis of polyunsaturated 15- and 18-membered macrocyclic silicohydrocarbons containing endocyclic CH = CH and C≡C groups in various structures. For the synthesis an intermolecular hydrosilylation reaction of specially synthesized polyfunctional silicohydrocarbons was applied.