- Lithiated 1,3-Disilabicyclo[1.1.0]butanes Synthesized via Selective Cleavage of Exocyclic Si-Si Bonds on Bridgehead Silicon Atoms
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Treatment of 1,3-di(t-butyldimethylsilyl)-1,3-disilabicyclo[1.1.0]butane 1a with excess lithium in THF provided 1,3-dilithio-1,3-disilabicyclo[1.1.0]butane 2 via reductive cleavage of the exocyclic Si-Si bonds at the bridgehead silicon atoms. In the single crystals obtained by recrystallization in the presence of 1,2-dimethoxyethane (DME), 2 exists as a solvent-separated ion pair, and its anionic part forms an aggregate that contains three lithium atoms sandwiched by two 1,3-disilabicyclo[1.1.0]butan-1,3-diide units. Treatment of 2 with chlorotriisopropylsilane provided triisopropylsilyl-substituted 1,3-disilabicyclo[1.1.0]butane 1b. The structural characteristics of 1b are close to that of the short-bond isomer, which is consistent with previous theoretical predictions concerning the steric effects of the bridgehead substituents on the structure of silabicyclo[1.1.0]butane.
- Akasaka, Naohiko,Ishida, Shintaro,Iwamoto, Takeaki,Kira, Mitsuo,Kobayashi, Akifumi,Motomatsu, Daiki,Tamura, Makoto,Yin, Dongzhu,Yokouchi, Yuki
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- Activation of Homolytic Si-Zn and Si-Hg Bond Cleavage, Mediated by a Pt0 Complex, via Novel Pt-Zn and Pt-Hg Compounds
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The thermally stable [(tBuMe2Si)2M] (M=Zn, Hg) generate R3Si. radicals in the presence of [(dmpe)Pt(PEt3)2] at 60-80 C. The reaction proceeds via hexacoordinate Pt complexes, (M=Zn (2 a and 2 b), M=Hg (3 a and 3 b)) which were isolated and characterized. Mild warming or photolysis of 2 or 3 lead to homolytic dissociation of the Pt-MSiR3 bond generating silyl radicals and novel unstable pentacoordinate platinum paramagnetic complexes (M=Zn (5), Hg (6)) whose structures were determined by EPR spectroscopy and DFT calculations. SiM City: The thermally stable [(tBuMe2Si)2M] (M=Zn, Hg) generate R3Si. radicals in the presence of [(dmpe)Pt(PEt3)2]. The enhancing effect of the Pt complex on the homolytic cleavage of the Si-M bonds in [(tBuMe2Si)2M] is mediated by formation of octahedral hexacoordinate Pt-M trinuclear complexes.
- Kratish, Yosi,Molev, Gregory,Kostenko, Arseni,Sheberla, Dennis,Tumanskii, Boris,Botoshansky, Mark,Shimada, Shigeru,Bravo-Zhivotovskii, Dmitry,Apeloig, Yitzhak
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- Disilane and preparation method thereof
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The invention discloses disilane and a preparation method thereof. The preparation method of disilane includes: subjecting a uniformly mixed reaction system containing tertiary hydrosilane and a catalyst to dehydrogenation reaction at a temperature ranging from -10DEG C to 120DEG C to obtain disilane, wherein the catalyst comprises a silver salt. The invention also discloses the disilane preparedby the method. The method for preparation of the disilane by catalyzing tertiary silane dehydrogenation with the silver salt adopts the silver salt to activate the Si-H bond in the silane so as to realize construction of disilane. Therefore, the invention provides an efficient and simple method for preparation of the compound, and the application prospect is wide.
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Paragraph 0070-0073
(2020/01/25)
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- Synthesis and cyclisation of boryl-and silylhydrazones
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Reactions of the lithium salts of the tert-butylmethylhydrazones Me 3C(Me)C=N-NLiR, (R = H, Me, CMe3) with fluorosilanes and -boranes in a molar ratio 1 : 1 gave the silyl-(1 - 3, 5, 6) and borylhydrazones (4, 8) Me3 C(Me)C=N-N(R)R′; 1: R = H, R′ = SiFMe 2 ; 2: R = H, R′ = SiMe2CMe3; 3: R = H, R′ = SiF(CMe3 )2; 4: R = H, R′ = BFN(SiMe 3)2; 5: R = Me3 C, R′ = SiF 2CMe3; 6: R = Me3C, R′ = F 2SiC(SiMe3)3; 8: R = Me3C, R′ = BFN(SiMe3)2. The lithiated hydrazone Me 2C=N-NH(Me) reacted with F3SiC(SiMe3) 3 to give the silylhydrazone Me2C=N- NHSiF 2C(SiMe3)3, 7. Because of the fluoro functionality of 1 and 4, the bis-hydrazonylsilane 9 and the bis-and tris-hydrazonylboranes 10 and 11 could be synthesised, (Me3C(Me)C=N- NH)2R; 9: R = SiMe2 , 10: R = BN(SiMe3 ) 2; 11: (Me3 C(Me)C=N-NH)3B. Starting from 2 and its lithium salt, secondary substitutions are possible. Bis(silyl)- and silyl(boryl)hydrazones are formed (12 - 15); Me3C(Me)C=N(R) (SiMe2CMe3) 12: R = SiFMe2; 13: R = SiF(CMe3)2; 14: R = SiF2CMe3; 15: R = BFN(SiMe3 )2. Ring closure occurs in the reaction of dilithiated Me2C=N- NHCMe3 with F2Si(CHMe 2)2. The 1,2-diaza-3-sila-5-cyclopentene 16 is isolated. The fluorofunctional silyl-hydrazones 7, 12, and 13 cyclise in reactions with t-BuLi to give 1,2-diaza-3-sila-5- cyclopentenes 17 - 20; RN(N=CR′-CH 2)R′′; 17: R =Me, R′ = Me3C, R″ = SiFC(SiMe3)3; 18: R = Me3C, R′ = SiMe2CMe3, R″ = SiMe2; 19: R =Me 3C, R′ = SiMe2CMe3, R″ = Si(CMe3)2. A 1,2- diaza-3-bora-5-cyclopentene 20 is the result of the reaction of 8 with t-BuLi: Me3CN(N=CCMe3- CH2)BN(SiMe3)2. The H-acidic methylene group of the five-membered ring in 20 can be lithiated with n-BuLi and substituted with fluorosilanes. Starting from 16 and 20, the silyl-substituted rings Me 3CN(N=CMe-CHR)Si(CHMe2)2 21 - 23 and 25 are obtained; 21: R = SiMe3; 22: R = SiF2C(SiMe 3)3; 23: R = SiF3; 25: Me3CN[N= CC(Me)3CHSiMe3]BN(SiMe3)2. Using SiF4 as fluorosilane, the main product is the difluorosilane containing two rings; F2Si[CHC(Me)=N-NCMe3- Si(CHMe 2)2]2. The methine group in 4-position of the silyl-substituted rings is also acidic and reacts with n-BuLi to give lithium salts which react with aminodifluoroboranes giving the ring compounds Me 3CN[N=C(CMe3)C(SiMe2R)(FBNR′SiMe 3)]SiMe2 26 - 28; 26: R = Me, R′ = CMe3; 27: R = F, R′ = CMe3 ; 28: R = F, R′ = SiMe3 . In contrast to the substitution reactions of fluorosilanes with lithiated rings, an unusual oxidation reaction occurs starting from lithiated Me 3CN(N=C(CMe3)CH2)Si(CHMe2)2 and ClSiMe2CMe3 to give 29, in which a C-C bond in 4- position links two five-membered rings. The disilane (Me3CSiMe 2)2 is formed as a by-product of this reaction. The combination of the N-SiF2CMe3-substituted hydrazones 5 and 14 with t-BuLi in a molar ratio 1 : 2 leads to the colourless, crystalline tricyclic products 30 and 31 which are dimeric 1,2-diaza-3-sila-3,5- cyclopentadienes. The molecular structures of 3, 6, 11, 30, and 31 are reported.
- Goerth, Martin,Schneider, Ute,Ott, Holger,Schulzke, Carola,Stalke, Dietmar,Klingebiel, Uwe
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experimental part
p. 587 - 602
(2010/10/01)
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- Direct construction of silicon-silicon bond by using the low-valent titanium reagent
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The reductive dimerization or polymerization of organochlorosilanes has been achieved by using the low-valent titanium reducing agent other than the alkali metals that are invariable used in the Wurtz-type coupling reaction. Applying this method, the corresponding disilanes or poly(methylvinylsilane) was obtained in good yields. The poly(methylvinylsilane) synthesized by this method is highly pure with a high molecular weight and a narrow molecular weight distribution (Mw/Mn = 1.6, Mn = 16,860).
- Lai, Guoqiao,Li, Zhifang,Huang, Jiabang,Jiang, Jianxiong,Qiu, Huayu,Shen, Yongjia
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p. 3559 - 3562
(2008/02/12)
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- Efficient formation and cleavage of disilanes by potassium-graphite. Silylation with silyl metal reagents
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Potassium-graphite laminate (C8K) very rapidly forms disilanes from chlorosilanes and then rapidly cleaves the disilanes to give silyl potassium reagents which can be converted into potassium silyl cuprates, -manganates, and -vanadates that are useful for various nucleophilic substitution and addition reactions.
- Fuerstner, Alois,Weidmann, Hans
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- Electrophilic Conversion of Oxiranes to Allylic Alcohols with tert-Butyldimethylsilyl Iodide
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tert-Butyldimethylsilyl iodide (I) is prepared from the reaction of iodine with (phenylseleno)-tert-butyldimethylsilane in acetonitrile.The reaction of oxiranes with 1 followed by treatment with 1,5-diazabicyclonon-5-ene gives accetable yields of allylic alcohols isolated as their tert-butyldimethylsilyl ethers.Ring opening involves cleavage of the bond to the more highly substituted carbon.
- Detty, Michael R.
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p. 924 - 926
(2007/10/02)
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