- Exhaustively Trichlorosilylated C1 and C2 Building Blocks: Beyond the Müller-Rochow Direct Process
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The Cl--induced heterolysis of the Si-Si bond in Si2Cl6 generates an [SiCl3]- ion as reactive intermediate. When carried out in the presence of CCl4 or Cl2C=CCl2 (CH2Cl2 solutions, room temperature or below), the reaction furnishes the monocarbanion [C(SiCl3)3]- ([A]- 92%) or the vicinal dianion [(Cl3Si)2C-C(SiCl3)2]2- ([B]2- 85%) in excellent yields. Starting from [B]2-, the tetrasilylethane (Cl3Si)2(H)C-C(H)(SiCl3)2 (H2B) and the tetrasilylethene (Cl3Si)2C=C(SiCl3)2 (B; 96%) are readily available through protonation (CF3SO3H) or oxidation (CuCl2), respectively. Equimolar mixtures of H2B/[B]2- or B/[B]2- quantitatively produce 2 equiv of the monoanion [HB]- or the blue radical anion [B?]-, respectively. Treatment of B with Cl- ions in the presence of CuCl2 furnishes the disilylethyne Cl3SiC≡CSiCl3 (C; 80%); in the presence of [HMe3N]Cl, the trisilylethene (Cl3Si)2C=C(H)SiCl3 (D; 72%) is obtained. Alkyne C undergoes a [4+2]-cycloaddition reaction with 2,3-dimethyl-1,3-butadiene (CH2Cl2, 50 °C, 3d) and thus provides access to 1,2-bis(trichlorosilyl)-4,5-dimethylbenzene (E1; 80%) after oxidation with DDQ. The corresponding 1,2-bis(trichlorosilyl)-3,4,5,6-tetraphenylbenzene (E2; 83%) was prepared from C and 2,3,4,5-tetraphenyl-2,4-cyclopentadien-1-one under CO extrusion at elevated temperatures (CH2Cl2, 180 °C, 4 d). All closed-shell products were characterized by 1H, 13C{1H}, and 29Si NMR spectroscopy; an EPR spectrum of [nBu4N][B?] was recorded. The molecular structures of [nBu4N][A], [nBu4N]2[B], B, E1, and E2 were further confirmed by single-crystal X-ray diffraction. On the basis of detailed experimental investigations, augmented by quantum-chemical calculations, plausible reaction mechanisms for the formation of [A]-, [B]2-, C, and D are postulated.
- Georg, Isabelle,Teichmann, Julian,Bursch, Markus,Tillmann, Jan,Endeward, Burkhard,Bolte, Michael,Lerner, Hans-Wolfram,Grimme, Stefan,Wagner, Matthias
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supporting information
p. 9696 - 9708
(2018/07/21)
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- Reaction of Hexachlorodisilane with Trichloroethynylsilane and 2-Propynyl Chloride in the Gas Phase
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Reaction of acetylenic compounds (trichloroethynylsilane and 2-propynyl chloride) with hexachlorodisilane in the gas phase at 450-520°C was studied. Main products of the reaction were identified, and a mechanism of their formation was proposed. It was shown that of the two reaction centers of 2-propynyl chloride (C=≡C and C-Cl) only the C-Cl bond is involved in reaction with dichlorosilylenes generated from hexachlorodisilane.
- Chernyshev,Komalenkova,Kapitova,Bykovchenko,Khromykh,Bochkarev
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p. 1043 - 1046
(2007/10/03)
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- Gas-phase reactions of hexachlorodisilane with chloroform, carbon tetrachloride, and Di- and tetrachloroethylenes
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Gas-phase reactions of hexachlorodisilane with chloroalkanes (CHCl3 and CCl4) and chloroalkenes (ClCH=CHCl and Cl2C=CCl2) are studied. Dichlorosilylenes generated from Si2Cl6 insert into the C-Cl bonds in chloroalkanes; with chloroalkenes, insertion into the C-Cl bonds occurs along with cyclo-addition to the C=C bonds.
- Chernyshev,Komalenkova,Kapitova,Bykovchenko
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p. 1113 - 1116
(2007/10/03)
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- Synthesis, Properties, and Structure of Some Silyl-Ethenes
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trans-1,2-Dichloro-1,2-bis(trichlorosilyl)ethene (1) was prepared from Cl3CSiCl3 and copper powder, and its structure determined by single crystal X-ray diffraction (monoclinic, space group P21/n, a = 7.297(1), b = 10.964(1), c = 7.988(1) Angstroem, β = 108.06(1) deg; R = 0.037, Rw = 0.066).Cl3SiCCSiCl3, 2, forms a cobalt cage cluster on reaction with Co2(CO)8 formulated as (CO)6Co2C2(SiCl3)2.Hydrosilylation with HSiCl3 gives tris(trichlorosilyl)ethene. - Bis(trimethylsilyl)ethine adds HSiCl3 to form 1-trichlorosilyl-1,2-bis(trimethylsilyl)ethene, which can be converted into the hydride with i-Bu2AlH.All compounds are model systems for CVD production of amorphous silicon a-Si:C. - Key words: - Silyl-ethene, Silyl-ethine, Alkenyl-silane, Alkinylsilane
- Schmidbaur, Hubert,Ebenhoech, Jan,Mueller, Gerhard
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p. 142 - 146
(2007/10/02)
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- Synthesis and Spectroscopic Characterization of Di- and Trisilylethenes
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Di- and trisilylethenes have been prepared by catalytic hydrosilylation of trimethylsilyl-, bis(trimethylsilyl)- and bis(trichlorosilyl)ethyne and converted into the hydrogenated derivatives by LiAlH4-reduction.The stereochemistry of the products and the effects of substitution of methyl vs. chlorine ligands on the NMR coupling constants J(29Si/1H) have been investigated by analysis of selectively (Me)-decoupled 29Si NMR spectra.From the results it has been concluded, that the catalytic hydrosilylation of silylated ethynes proceeds in a stereospecific syn fashion yield ing trans adducts.Substitution of methyl by chlorine at one or two Si-atoms in tris(trimethylsilyl)ethene leads to an increase of the coupling constant J(29Si/1H vinyl) with the chlorinated Si-atoms and reduces the values for those Si-atoms, where the methyl groups are retained. - Keywords: Di- and Trisilylethenes, Catalytic Hydrosilylation
- Schmidbaur, H.,Ebenhoech, J.
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p. 1543 - 1548
(2007/10/02)
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