- Reaktionen von Trimethylsiloxychlorsilanen (Me3SiO)Me2-nPhnSiCl (n = 0, 1, 2) mit Lithium - Bildung von Trimethylsiloxy-substituierten Silyl- und Disilanyllithiumverbindungen sowie Di- und Trisilanen
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The trimethylsiloxychlorosilanes (Me3SiO)Me2-nPhnSiCl (1: n=0; 2: n=1; 3: n=2) were allowed to react with lithium metal in tetrahydrofuran (THF) and in a mixture of THF-diethylether-n-pentane in volume ratio 4:1:1 (Trapp mixture). The reaction of 1 with lithium metal in THF under refluxing leads to the homo-coupling product [(Me3SiO)Me2Si]2 (4). A mixture of 1 and Me3SiCl in molar ratio 1:2 reacts with lithium metal in THF to give 4 and the cross-coupling product (Me3SiO)Me2SiSiMe3 (7). The silyllithium derivatives Me3SiO(SiMePh)nLi (8: n = 1; 9: n = 2; 10: n = 3) and Me3SiSiMePhLi (11) are formed in the reaction of 2 with lithium metal in THF at -78°C and in the Trapp mixture at -110°C. Main product in both cases is 9. 8-11 are trapped by Me3SiCl and HMe2SiCl. The trapping products (Me3SiO)SiMePhSiMe3 (13a), Me3SiO(SiMePh)2SiMe2R (14a, 14b; a: R = Me, b: R = H), Me3SiO(SiMePh)3SiMe2R (15a, 15b) and Me3SiSiMePhSiMe2R (16a, 16b) are obtained. The reaction of 3 with lithium metal like 2 produces the silyllithium derivatives Me3SiO(SiPh2)nLi (18: n = 1, 19: n = 2) and Me3SiSiPh2Li (20), wich are trapped by Me3SiCl and HMe2SiCl to give the corresponding disilanes (Me3SiO)SiPh2SiMe2R (23a, 23b) and trisilanes Me3SiO(SiPh2)2SiMe2R (24a, 24b) as well as Me3SiSiPh2SiMe2R (25a, 25b). In addition to 18, 19 and 20 LiSiPh2SiPh2Li (21) is formed in a small amount in the reaction of 3 with lithium metal at -78°C to afford tetrasilanes [RMe2SiPh2Si]2 (26a, 26b) after trapping by Me3SiCl and HMe2SiCl. The disilane (Me3SiO)SiMeR′SiMe3 (17) (R′ = 3,4,5,6-tetrakis(trimethylsilyl)cyclohex-1-enyl) is produced by reaction of a mixture of 2 and Me3SiCl in molar ratio 1:6 with 6 equivalents of lithium at -78°C in THF. The reaction of a mixture of 3 and Me3SiCl in the molar ratio 1:10 with 11 equivalents of lithium under the same conditions gives (Me3SiO)SiR′2SiMe3 (27).
- Harloff, Joerg,Popowski, Eckhard,Fuhrmann, Hans
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p. 136 - 146
(2007/10/03)
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- Electroreductive Synthesis of Polysilanes, Polygermanes, and Related Polymers with Magnesium Electrodes
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The electroreduction of alkylaryldichlorosilane carried out with Mg cathode and anode in a single compartment cell gave high molecular weight poly(alkylarylsilane) (Mn = 5200-31000, Mw/Mn = 1.4-1.8) in 5-79% yield. The effects of electrode material, monomer concentration, amount of supplied electricity, and ultrasound were investigated. This electroreductive method was also successfully applied to the synthesis of polygermanes, silane-geramane copolymers, and also poly[p-(disilanylene)phenylenes].
- Kashimura, Shigenori,Ishifune, Manabu,Yamashita, Natsuki,Bu, Hang-Bom,Takebayashi, Masakatsu,Kitajima, Satsuki,Yoshiwara, Daisuke,Kataoka, Yasuki,Nishida, Ryoichi,Kawasaki, Shin-Ichi,Murase, Hiroaki,Shono, Tatsuya
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p. 6615 - 6621
(2007/10/03)
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- Base catalysed hydrogenation of methylbromooligosilanes with trialkylstannanes, identification of the first methylbromohydrogenoligosilanes
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The Lewis base catalysed hydrogenation of methylchlorooligsilanes with trialkylstannanes can also be applied to the hydrogenation of methylbromooligosilanes. In this way methylbromohydrogenoligosilanes were prepared for the first time. Methylbromotrisilanes with an > SiBrMe middle group (e.g. SiBrMe2-SiBrMe-SiBrMe2) are hydrogenated First at this silicon atom under formation of an > SiHMe group (e.g. SiBrMe2-SiHMe-SiBrMe2). Brominated silanes containing a quarternary Si(Si)4 unit (e.g. Si(SiBrMe2)4) do not react with trialkylstannanes.
- Herzog,Roewer
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p. 117 - 124
(2007/10/03)
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- Electroreductive synthesis of some functionalized polysilanes and related polymers
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Polysilanes having hydroxyl and related Functional groups have been synthesized by the electroreduction of appropriate dichlorosilanes with Mg electrode, and a vinyl polymer which has oligosilane unit in the side chain has also been synthesized.
- Kashimura, Shigenori,Ishifune, Manabu,Bu, Hang-Bom,Takebayashi, Masakatsu,Kitajima, Satsuki,Yoshihara, Daisuke,Nishida, Ryoichi,Kawasaki, Shin-Ichi,Murase, Hiroaki,Shono, Tatsuya
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p. 4607 - 4610
(2007/10/03)
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- υ-Ray- and UV-induced Generation of Methyl(phenyl)silylene and Silene Species from Heptamethyl-2-phenyltrisilane
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A benzene solution of heptamethyl-2-phenyltrisilane (1) has been irradiated with γ-rays in the presence of methanol.Hexamethyldisilane, methoxymethyl(phenyl)silane (2) and a 1-methoxytetramethyldisilanyl- and trimethylsilyl-substituted cyclohexadiene (3) were produced.The formation of 2 and 3 can be interpreted in terms of reactions of methanol with methyl(phenyl)silylene and a silicon-carbon double-bonded intermediate (silene), respectively.These intermediates are generated as follows.Benzene is first excited by γ-rays and by collisions the energy transfers to 1.Excited 1 decomposes to give methyl(phenyl)silylene or undergoes rearrangement to a silene intermediate as when 1 is excited by UV light.A kinetic study revealed that the energy transfer in the γ-irradiated system is the same as that in a UV-irradiated system.
- Nakao, Ren,Oka, Kunio,Irie, Setsuko,Dohmaru, Takaaki,Abe, Yasuo,et al.
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p. 755 - 757
(2007/10/02)
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- L'electrosynthese, une voie simple d'acces aux di- et polysilanes
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Electrochemical reduction of chlorosilanes, at constant current intensity, in a single compartment cell fitted with a sacrificial aluminium anode, is a practical and convenient route to di-, tri-, and poly-silanes.
- Biran, C.,Bordeau, M.,Pons, P.,Leger, M.-P.,Dunogues, J.
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p. C17 - C20
(2007/10/02)
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