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  • 1
    Electronic Resource
    Electronic Resource
    Hexacoordinate Silicon-Azomethine Complexes: Synthesis, Characterization, and Properties (1999)
    Springer
    Monatshefte für Chemie 130 (1999), S. 117-132 
    Details
    ISSN: 1434-4475
    Keywords: Keywords. Salen complexes; Hexacoordinate silicon; Silicon complexes.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  N,N′-Ethylen-bis(2-hydroxyacetophenonimin)=salen *H2 und N,N′-Ethylen-bis(3,5-di-tert-butyl-salicylidenimin)=salen
    Notes: Summary.  N,N′-Ethylene-bis(2-hydroxyacetophenoneimine)=salen *H2 and N,N′-ethylene-bis(3,5-di-tert-butyl-salicylideneimine)=salen
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00000113
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Preparation, Characterization, and Properties of Various Novel Ionic Derivatives of Pentacarbonyltungsten (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1813-1820 
    Details
    ISSN: 1434-1948
    Keywords: Tungsten ; Carbonyl complexes ; Undecamethylcyclohexasilyl ; Transition metal silicon compounds ; Anions ; Tungsten silicide ; Silicon ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complexes [Li(DIME)2][W(CO)5L] [L = OCN 2, NCS 3a, PPh24, SiMe2Ph 8, N(SiMe3)29, CH2Ph 10, Si6Me1111; DIME = diethylene glycol dimethyl ether] have been prepared by reaction of [Li(DIME)2][W(CO)5I] (1) with KOCN, KSCN, NaPPh2, LiSiMe2Ph, LiN(SiMe3)2, PhCH2MgCl, and KSi6Me11, respectively. Photochemical ligand substitution in W(CO)6 has been used as an alternative method for the preparation of pentacarbonyl tungstates; [K(DIME)2][W(CO)5NCS] (3b), [Na(DIME)2][W(CO)5N3] (5), [Li(DIME)2][W2(CO)10(μ-H)] (6), and [K(DIME)2][W2(CO)10(μ-CN)] (7) were synthesized in this manner. The molecular structure of [Li(DIME)2][W(CO)5Si6Me11] (11) has been determined by X-ray diffraction analysis. The spectral and chemical properties of 2-11 are discussed. Pyrolysis of 11leads to tungsten silicide and tungsten carbide.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    Intramolekulare C—H-Aktivierung bei der Reaktion von Bis(benzylcyclopentadienyl)zirconiumdichlorid mit Vinyllithium  -  Bildung eines Crotyl-zirconacyclus (1993)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 1488-1490 
    Details
    ISSN: 0044-2313
    Keywords: Bis(benzylcyclopentadienyl)zirconium dichloride ; C—H Activation ; Orthometallation Reaction ; Crotylzirconium Compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Intramolecular C—H Activation at Reaction of Bis(benzylcyclopentadienyl)zirconium Dichloride with Vinyllithium  -  Formation of a Crotyl ZirconacyclusBis(benzylcyclopentadienyl)zirconium dichloride, (C6H5CH2—C5H4)2ZrCl2 (V), reacts with vinyl lithium with formation of the chiral compound (C6H5CH2—C5H4)— —CH2CH=CHCH3 (IX) as the product of vinyl group coupling and an orthometallation reaction. The reaction mechanism and the 13C n.m.r. spectrum are discussed.
    Notes: Bei der Reaktion von Bis(benzylcyclopentadienyl)zirconiumdichlorid, (C6H5CH2—C5H4)2ZrCl2 (V), mit Vinyllithium entsteht nicht das entsprechende Divinylderivat, sondern die chirale Crotylverbindung der Formel (C6H5CH2—C5H4)— —CH2CH=CHCH3 (IX) als Produkt einer Kopplung von Vinylgruppen und einer Orthometallierungsreaktion. Der Bildungsmechanismus und das 13C-NMR-Spektrum werden diskutiert.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19936190828
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  • 4
    Electronic Resource
    Electronic Resource
    Vinylierung und 91Zr-NMR-Spektren von Substituierten Zirconocendichloriden (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 1455-1462 
    Details
    ISSN: 0044-2313
    Keywords: Zirconocene complexes ; vinylation reactions ; metallocycles ; butadiene complexes ; 91Zr n.m.r. spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Vinylation and 91Zr N.M.R. Spectra of substituted Zirconocene DichloridesSubstituted zirconocene dichlorides react with vinyl lithium with formation of zirconacyclopent-2-enes, Cp2ZrCH = CHCH2CH2, or zirconocene butadiene complexes, Cp2Zr(C4H6). The compounds obtained were characterized by their 1H and 13C n.m.r. spectra.The 91Zr n.m.r. chemical shifts of substituted zirconocene dichlorides correlate with the bond angles Cp′—Zr—Cp′ and Cl—Zr—Cl respectively. They can be used to estimate the reaction behaviour of zirconocene dichlorides.
    Notes: Bei Reaktionen substituierter Zirconocendichloride, Cp2ZrCl2, mit Vinyllithium entstehen in Abhängigkeit von der Anzahl und der Raumerfüllung der Substituenten Zirconacyclopent-2-ene, Cp2H2, oder Zirconocen-butadien-Komplexe, Cp2Zr(C4H6). Diese Verbindungen wurden durch ihre 1H- und 13C-NMR-Spektren charakterisiert.Die Werte der 91Zr-NMR-chemischen Verschiebungen der substituierten Cp′2ZrCl2 stehen in Beziehung zu den jeweiligen Bindungswinkeln Cp′—Zr—Cp′ bzw. Cl—Zr—Cl und sind damit als empirische Parameter für die Abschätzung des Reaktionsverhaltens von Zirconocendichloriden geeignet.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19946200823
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  • 5
    Electronic Resource
    Electronic Resource
    Organosilicon Polymers - Synthesis, Architecture, Reactivity and Applications (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 11 (1997), S. 71-106 
    Details
    ISSN: 0268-2605
    Keywords: polysilane ; poly(carbosilane) ; disilane ; oligosilane ; SiC fiber ; SiC precursor ; dehalocoupling ; dehydropolymerization ; disproportionation ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tailoring of polysilanes with given architectures and reactivities is a great challenge in the field of SiC pre-ceramic polymers. This paper reviews recent polysilane and related copolymer synthesis reactions.It is shown that the Wurtz-type polymerization of dichloro-, trichloro- or tetrachloro-silanes, so far the most extensively studied, enables access to a large variety of architectures ranging from one- to three-dimensional (3D) topologies, and based on secondary 〉SiR2, tertiary RSi(Si)3 or quaternary Si(Si)4 silicon units in the polymer backbone. These polysilanes usually present an intrinsic low reactivity, detrimental for fiber processing. Examples are given to illustrate how this reactivity can be increased by secondary substitution reactions, which create reactive entities that can favor further crosslinking reactions.Secondly a novel route involving heterogeneously catalyzed disproportionation of chloromethyldisilanes, developed in our laboratory, is reviewed which offers a direct access to polysilyne-type 3D architecture constituted by arrangements of fused rings. The Lewis-base catalyzed disproportionation mechanism is discussed and seems to involve donor-stabilized silylenes as key intermediates in the polymer formation process. The experimental results are supported by ab-initio quantum chemical calculations.Silylenes attack the Si sites of higher functionality causing a high regioselectivity for the exclusive formation of branched oligosilanes. The oligomers undergo thermally induced branching and crosslinking reactions leading to poly(chloromethylsilane)s. Obviously, there are analogies to the oligomer and polymer formation of the transition-metal complex catalyzed dehydropolymerzation of methyldisilanes. Poly(chloromethylsilane)s exhibit a high reactivity due to the presence of Si-Cl bonds.Disproportionation of chloromethyldisilanes in presence of olefins such as styrene provides promising polymer precursors for SiC fibers. Their rheological properties have been investigated for various styrene contents. The polymer fibers spun from melt are cured under ammonia, and then pyrolyzed to silicon carbide fibers, showing temperature resistance up to 1500 °C. © 1996 by John Wiley & Sons, Ltd.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
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