- Synthesis of α,ω-dihalopermethyloligosilanes and silane-siloxane copolymers
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α,ω-Dibromopermethyloligosilanes, Br(SiMe2)nBr (n = 2-4, 6), were prepared by the reaction of dodecamethylcyclohexasilane with bromine. The reaction of (Me2Si)6 with MCl4 (M = Sn, Ti) proceeds with the cleavage of Si-Si-and Si-C-bonds with the formation of α,ω-dichloropermethyloligosilanes, Cl(SiMe2)nCI (n = 2-4, 6), and chloro derivatives of cyclohexasilane, ClmSi6Me12-m (m = 1, 2). Silane-siloxane copolymers of regular structure were obtained by heterofunctional copolycondensation of α,ω-dihalopermethyloligosilanes with 1,5-dihydroxyhexamethyltrisiloxane.
- Chernyavskii,Zavin
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p. 1449 - 1453
(2007/10/03)
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- REACTIONS OF 1,2-DIMETHOXYTETRAMETHYLDISILANE WITH STYRENES: FORMATION OF A NEW TYPE OF SILACYCLOPENTANES HAVING PHENYL SUBSTITUENTS ON RING CARBONS
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The reaction of 1,2-dimethoxytetramethyldisilane with styrene and α-methylstyrene in the presence of NaOMe catalyst in tetrahydrofuran (THF) gave the new silacyclopentanes 1,1-dimethyl-2,4-diphenyl-1-silacyclopentane (IIIa) and 1,1,2,4-tetramethyl-2,4-diphenyl-1-silacyclopentane (IIIb), respectively.These silacyclopentanes were found to exist as cis-trans mixtures.The use of sodium metal in place of NaOMe afforded similar results.Reactions of a polysilane mixture, MeO(SiMe2)nOMe (n 3), with the styrenes also gave similar results.In some cases, polysilacycloalkanes such as 1,2,3-trisilacyclopentanes (IV) and 1,2,3,4-tetrasilacyclohexanes (V) were obtained as by-products.A mechanism for the formation of the silacyclopentanes and polysilacycloalkanes is presented.It was found that electron impact decomposition of silacyclopentanes IIIa and IIIb, trisilacycloalkane IV and tetrasilacycloalkane V gave molecular ions corresponding to the silacyclopropane, cyclotrisilane and cyclotetrasilane systems.
- Watanabe, Hamao,Inose, Jun,Muraoka, Tsutomu,Saito, Masayuki,Nagai, Yoichiro
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p. 329 - 342
(2007/10/02)
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- The Permethylcyclosilanes (Me2Si)5 through (Me2Si)35
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The cyclic permethylpolysilanes (Me2Si)n, where n = 5-35, are all formed when dimethyldichlorosilane (Me2SiCl2) is added slowly to sodium-potassium (Na/K) alloy in tetrahydrofuran (THF).NMR, UV, and vibrational spectra are reported for compounds n = 5-19.The 13C NMR and 1H NMR spectra are explained in terms of methyl-methyl group interactions.Raman and IR spectra are assigned and partially explained on the basis of a standing wave model.
- Brough, Lawrence F.,West, Robert
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p. 3049 - 3056
(2007/10/02)
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