- Building blocks for oligomeric siloxanes –selective chlorination of hydrido-siloxanes
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A new method was developed to achieve highly selective monochlorination of α,ω-dihydridosiloxanes, ((H)Me2SiO-(SiMe2O)n-SiMe2(H), n = 0–2; (H)R2Si–O-SiR2(H); R = Me, iPr, Ph; 3,5-dihydridooctamethyltetrasiloxane, Me3SiO-(Si(H)MeO)2–SiMe3) with trichloroisocyanuric acid (TCCA). The dependence of the selectivity of the monochlorination on the siloxane chain length is also discussed.
- Hafner, Thomas,Torvisco, Ana,Uhlig, Frank
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supporting information
p. 1 - 4
(2018/09/11)
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- POLYARYLACETYLENES CONTAINING SILOXANE, SILANE, AND CARBORANE MOIETIES
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Disclosed herein are the compounds shown below. Each R is an organic group, Cb is a carborane group, and —C6H4— is phenylene. The value of each m is a nonnegative integer, q is 0 or 1, with the proviso that if q is 0 then m is 0 or 1, p is a positive integer, r is a positive integer, and n is an integer greater than or equal to 10. Also disclosed are methods of making and crosslinking the compounds. [in-line-formulae]—{SiR2—([O]q—SiR2)m-[Cb-SiR2—([O]q—SiR2)m]p—C≡C—C6H4—C≡C}—[/in-line-formulae] [in-line-formulae]—{SiR2—(O—SiR2)m—C≡C—C6H4—C≡C}n—;[/in-line-formulae] [in-line-formulae]—{SiR2—([O]q—SiR2)m—[C≡C—C6H4—C≡C—SiR2—([O]q—SiR2)m]p-Cb-[SiR2—([O]q—SiR2)m-Cb]r}-[/in-line-formulae]
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- REACTION OF ALLYL HALIDES WITH DIMETHYLPHENYLSILANE AND HEXAMETHYLTRISILOXANE IN THE PRESENCE OF HEXACHLOROPLATINIC ACID
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The reaction of dimethylphenylsilane with allyl chloride yields γ-chloropropyldimethylphenylsilane and dimethylphenylchlorosilane, whereas that with allyl bromide results in dimethylphenylbromosilane only.Hydrosilylation of allyl halides with 1,1,3,3,5,5-hexamethyltrisiloxane yields a mixture of various symmetric and asymmetric adducts at both Si-H bonds of the trisiloxane.
- Zavin, B. G.,Pryakhina, T. A.,Strelkova, T. V.,Kireev, V. V.,Astrina, V. I.,Pilipkova, A. Yu.
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p. 568 - 569
(2007/10/02)
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- Lanthanocene (Ln = PrIII, YbIII) chlorides involving tetramethyldisiloxane-interlinked cyclopentadienyl ligands
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Two new lanthanocenophanes PrIIICl*THF>x (2; x=1 or 2) and YbIIICl>2 (3), were made from LnCl3 (Ln=Pr or Yb) and K2 in THF.The 1H NMR spectra of THF-d8 solutions of paramagnetic 2 (at +35 to -25 deg C) and 3 (at 8 (at > 10 deg C), respectively, display somewhat less complex 1H NMR spectra consistent with a virtually symmetrical position of the Me2SiOSiMe2 unit with respect to the cent-Ln-cent' plane (cent = C5H4Si centroid).A low temperature (-100 deg C) single-crystal X-ray study of 3 has confirmed the presence of centrosymmetric, Cl-bridged dimers in which the molecular configuration of the mononuclear YbIIICl2 units correspond to that of the previously described complex IVCl2> (1).The high-resolution mass spectrum of 3 displays several signals from dinuclear fragments, the B/E-linked scans of which suggest, inter alia, intramolecular reorientation of at least one O(Me2SiC5H4)2 ligand from the chelating into a metal-bridging position.Key words: Ytterbium; Praseodymium; Metallocenes; Lanthanides; Chiral metallocenophanes; Crystal structure
- Graeper, Jens,Fischer, R. Dieter,Paolucci, Gino
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- REACTION OF OCTAMETHYLCYCLOTETRASILOXANE AND PERMETHYLOLIGOSILOXANES WITH ACYL CHLORIDES IN THE PRESENCE OF CoCl2
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Octamethylcyclotetrasiloxane is cleaved quantitatively by acetyl chloride (1:1 molar ratio) in the presence of anhydrous CoCl2 in acetonitrile at room temperature to form primarily α-chloro-ω-acetoxyoligodimethylsiloxanes nOCOCH3 (n = 0-3; yield, 60-65percent)>.In the presence of an equimolar amount of trimethylacetoxysilane of hexamethyldisiloxane, the major reaction products are α-methyl-ω-acetoxyoligodimethylsiloxanes nOCOCH3 (n = 4-6; yield, 65-70percent)>.
- Basenko, S. V.,Ogorodnikova, E. I.,Vitkovskii, V. Yu.,Mirskov, R. G.,Voronkov, M. G.
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- GAS-PHASE REACTIONS OF (BENZYLOXY)TRICHLOROSILANE WITH HEXAMETHYLCYCLOTRISILOXANE AND OCTAMETHYLCYCLOTETRASILOXANE
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Dichlorosilanone generated by the pyrolysis of (benzyloxy)trichlorosilane in the temperature range 500-620 deg C is inserted in a specific way into an Si-O bond in the cyclosiloxanes D3 and D4 with the formation of new cyclosiloxanes containing functional SiCl2 groups.
- Chernyshev, E. A.,Mudrova, N. A.,Krasnova, T. L.,Ushakov, Yu. M.,Petrunin, A. B.,Kuznetsova, M. G.
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p. 1076 - 1081
(2007/10/02)
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- A Convenient Synthesis of α,ω-Difunctionalized Linear Dimethylsiloxanes with Definite Chain Lengths
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α,ω-Difunctionalized linear dimethylsiloxanes with definite chain lengths are conveniently prepared by the inorganic-solid-catalyzed ring cleavage of cyclodimethylsiloxanes with dimethylchlorosilane and water under very mild conditions.
- Yoshino, Koji,Kawamata, Akira,Uchida, Hiroaki,Kabe, Yoshio
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p. 2133 - 2136
(2007/10/02)
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