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  • 1
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    Triple C–H Bond Activation of a Nickel-Bound Methyl Group: Synthesis and X-Ray Structure of a Carbide Cluster (NiCp)6(μ6-C) (2012)
    American Chemical Society
    Details
    Publication Date: 2012-07-25
    Print ISSN: 0020-1669
    Electronic ISSN: 1520-510X
    Topics: Chemistry and Pharmacology
    Published by American Chemical Society
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  • 2
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    Tris(.eta.5-cyclopentadienyl)(.mu.3-alkylidyne)trinickel clusters: preparation, characterization, and molecular structure (1988)
    American Chemical Society
    Details
    Publication Date: 1988-09-01
    Print ISSN: 0276-7333
    Electronic ISSN: 1520-6041
    Topics: Chemistry and Pharmacology
    Published by American Chemical Society
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  • 3
    Electronic Resource
    Electronic Resource
    Tris(.eta.5-cyclopentadienyl)(.mu.3-alkylidyne)trinickel clusters: preparation, characterization, and molecular structure (1988)
    s.l. : American Chemical Society
    Organometallics 7 (1988), S. 2038-2040 
    Details
    ISSN: 1520-6041
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/om00099a022
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis of a tris(η5-Cyclopentadienyl)(μ3-Methylidyne)trinickel cluster and its role as precursor for the tris(η5-cyclopentadienyl)(μ3-ethylidyne)trinickel cluster (1998)
    Springer
    Transition metal chemistry 23 (1998), S. 301-303 
    Details
    ISSN: 1572-901X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The new tris(η5-cyclopentadienyl)(μ3-methylidyne)trinickel cluster (NiCp)3CH was obtained by slow thermal decomposition of (η2-hex-1-ene)(η5-cyclopentadienyl)-methylnickel. As well as the (methylidyne)trinickel cluster, the known (ethylidyne)trinickel cluster (NiCp)3CMe was also produced in the reaction, at a ca. 1:1 molar ratio. It appears that the (methylidyne)trinickel cluster plays a key role in the formation of the C—C bond in this reaction and is a precursor of the (ethylidyne)trinickel cluster.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1015769102405
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  • 5
    Electronic Resource
    Electronic Resource
    (η2-Alken)(η5-cyclopentadienyl)organylnickel-Komplexe (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3231-3254 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (η2-Alkene)(η5-cyclopentadienyl)organylnickel ComplexesThe (cyclopentadienyl)organylnickel species A, which is formed by reaction of nickelocene (1) with organolithium or organomagnesium halides, can be stabilized by complexation to the C = C bond of an olefin. Below ca. -30°C, the organyllithium compounds react with 1 and olefins to give the (η2-alkene)(η5-cyclopentadienyl)organylnickel complexes 2a-j (alkene: ethylene), 7-14 (alkene: propene) as well as the related methylnickel derivatives 15-17 and 22-25 with alkenes of different types.  - Only one C=C bond of butadiene complexes to give 18, while in the case of substituted 1,3-alkadienes the least substituted double bond is complexed. Temperature dependent NMR spectra are observed; in the case of the CH2=CHR and CH2=CR1R2 complexes as the result of rotation of the alkene around the coordination axis two rotamers can be observed at ca. -60°C. The ability of the organylnickel bond to add to complexed ethylene decreases in the order Ph-Ni (to 28) 〈 c-C3H5-Ni (to 29) 〈 Me-Ni (to 2e). 2d catalyzes the oligomerisation of ethylene at 120°C to give a mixture of butene, hexene, and octene.
    Notes: Das bei der Umsetzung von Nickelocen (1) mit Organylmagnesiumhalogenid bzw. Organyllithium primär entstehende (Cyclopentadienyl)organylnickel A läßt sich durch Komplexierung an die C = C-Bindung eines Olefins stabilisieren. Unterhalb ca. -30°C lassen sich mit Organyllithium die (η2-Alken)(η5-cyclopentadienyl)organylnickel-Komplexe 2a-j (Alken: Ethylen), 7-14 (Alken: Propen) sowie die Methylnickel-Derivate gleichen Typs 15-17 und 22-25 mit verschiedenartigen Alkenen erhalten. Bei Butadien komplexiert nur eine C = C-Bindung zu 18, bei unsymmetrisch substituierten Butadienen ist dies die geringer substituierte Bindung.  -  Rotation des Alkens um die Koordinationsbindungsachse bedingt temperaturabhängige NMR-Spektren; bei Alkenen der Typen CH2=CHR und CH2=CR1R2 sind bei ca. -60°C zwei Rotamere beobachtbar. Die Fähigkeit der Organyl-Nickel-Bindung zur Addition an komplexiertes Ethylen sinkt in der Reihe Ph-Ni (zu 28) 〈 c-C3H5-Ni (zu 29 〈 Me-Ni (zu 2e). 2d katalysiert bei 120°C die Oligomerisierung von Ethylen zu einem Gemisch von Buten, Hexen und Octen.
    Additional Material: 15 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841171109
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  • 6
    Electronic Resource
    Electronic Resource
    Copolymerization and homopolymerization reactions in systems containing electron-donor monomer, electron-acceptor monomer, and lewis acid (1978)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 16 (1978), S. 867-875 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Investigations of the copolymerization of acrylonitrile, methacrylonitrile, methyl acrylate, methyl methacrylate, acrylic acid, acryloyl chloride, methyl vinyl ketone, and acrolein with styrene, and of acrylonitrile with acenaphthylene and 1,3-cyclopentadiene in the presence of Lewis acids as catalysts have been carried out. It was found that the free-radical alternating copolymerization and ionic copolymerization or homopolymerization reactions can proceed in these systems. The yield of the competitive free-radical and ionic reactions was related to the type of monomers and strength of the Lewis acid. The mechanism of the catalytic effect of Lewis acids in the reactions studied is discussed.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1978.170160502
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  • 7
    Electronic Resource
    Electronic Resource
    Polymerization of complexes formed by 4-vinylpyridine with alkylaluminium compounds and aluminium chloride (1970)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 136 (1970), S. 137-146 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurde gefunden, daß Komplexe aus 4-Vinylpyridin und Äthyl- oder Methylaluminiumverbindungen oder Aluminiumchlorid keine Copolymeren mit Äthylen, Propylen, Vinylchlorid, Styrol, Butadien und 1-Vinyl-3-cyclohexen ergeben. In Gegenwart von Propylen bildet sich Polyvinylpyridin. Die Polymerisation der Komplexe, die sich aus 4-Vinylpyridin mit Methylaluminiumverbindungen bilden, wurde untersucht. Es wird ein anionischer Mechanismus der Initiierung durch Alkylanionen, die aus der aluminiumorganischen Verbindung entstehen, vorgeschlagen. Die Wirkung von Propylen und Lösungsmittel auf die Ausbeute wird besprochen. Der Mechanismus der Copolymerisation solcher Komplexe wird behandelt.
    Notes: Complexes of 4-vinylpyridine with ethylaluminium compounds, methylaluminium compounds, and aluminium chloride were found to yield no copolymers with ethylene, propylene, vinyl chloride, styrene, butadiene, and 1-vinyl-3-cyclohexene. With propylene, poly(vinylpyridine) is formed. Polymerization was studied of complexes formed by 4-vinyl-pyridine with methylaluminium compounds. An anionic mechanism of initiation by alkyl anions originating from organoaluminium compound has been suggested. The effects of propylene and solvent on the reaction yield are discussed. The mechanism of complex copolymerization is considered.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1970.021360112
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  • 8
    Electronic Resource
    Electronic Resource
    Alternating copolymerization of conjugated vinyl monomers with isobutylene, styrene, and vinyl acetate in the presence of ethylaluminum dichloride (1972)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 156 (1972), S. 251-258 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Copolymerisation von Acrylnitril (AN), Methacrylnitril (MAN), Methylvinylketon (MVK), Methylacrylat (MA) und Methylmethacrylat (MMA) - als Komplex mit Äthylaluminiumdichlorid - mit Isobutylen (IB), Styrol (St) und Vinylacetat (VA) wurde untersucht. Es wurde gefunden, daß sie spontan fortschreitet und alternierende Copolymere ergibt. Die Reaktivität der polaren, in einem Komplex mit C2H5AlCl2 gebundenen Monomeren, wurde bei der Copolymerisation mit St und IB bestimmt. Dabei wurde gefunden, daß die Reaktivität in folgender Reihe abnimmt: AN 〉 MAN 〉 MA 〉 MMA bzw. AN 〉 MVK 〉 MA (MAN und MMA geben keine Copolymeren mit IB). Es wurde eine Beziehung zwischen der Ausbeute der Copolymerisation und dem e-Wert der nicht komplex gebundenen untersuchten Monomeren aufgefunden.
    Notes: Copolymerization of acrylonitrile (AN), methacrylonitrile (MAN), methyl vinyl ketone (MVK), methyl acrylate (MA), and methyl methacrylate (MMA), complexed by ethylaluminum dichloride, with isobutylene (IB), styrene (St), and vinyl acetate (VA) was studied. It was found to proceed spontaneously resulting alternating copolymers. The reactivity of the polar monomers complexed by EtAlCl2 in their copolymerization with St and IB was investigated and found to decrease in the following order: AN 〉 MAN 〉 MA 〉 MMA and AN 〉 MVK 〉 MA, respectively, (MAN and MMA do not give copolymers with IB). A correlation of the copolymerization yield with the e value for the uncomplexed monomers investigated was observed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1972.021560119
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  • 9
    Electronic Resource
    Electronic Resource
    On the catalytic activity of alkylaluminum compounds in acrylonitrile-propylene alternating copolymerization (1974)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 175 (1974), S. 3411-3415 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es konnte gezeigt werden, daß die alternierende Copolymerisation von Acrylnitril und Propylen in Gegenwart der aluminiumorganischen Verbindungen RAlCl2 durch freie Radikale, die durch Spaltung der Al—R Bindung gebildet werden, initiiert wird. Die Radikale R. und Al. wurden unter Polymerisationsbedingungen mit Hilfe der ESR-Spektroskopie nachgewiesen. Die Ausbeute und der Staudinger-Index des Copolymers von Acrylnitril und Propylen wurden in Abhängigkeit vom Charakter der organischen Substituenten in der aluminiumorganischen Verbindung untersucht. Die Ergebnisse werden in Hinblick auf den bereits von den Autoren formulierten Initiierungsmechanismus diskutiert.
    Notes: The alternating copolymerization of acrylonitrile and propylene in the presence of organoaluminium compounds of the type RAlCl2 could be shown to be initiated by free radicals formed by cleavage of the Al—R bond. The R. and Al. radicals were detected under polymerization conditions by ESR spectroscopy. The yield and the intrinsic viscosity of the acrylonitrile/propylene copolymer were studied in relation to the nature of organic substituents in the organoaluminium compounds. The results were discussed in terms of an initiation mechanism previously postulated by the authors.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1974.021751207
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  • 10
    Electronic Resource
    Electronic Resource
    Vinyl monomer complexes in copolymerization processes. Studies on the complexes of acrylonitrile and methyl methacrylate with lewis acids (1976)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 177 (1976), S. 2627-2635 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurden IR-, NMR- und UV-Untersuchungen der Acrylnitril- und Methylmethacrylat-Komplexe 1 und 2 mit verschiedenen Lewis-Säuren durchgeführt und der Einfluß der Lewis-Säure-Stärke auf die Größe der Induktionseffekte und auf die Delokalisierung der π-Elektronen bestimmt. Mit Erhöhung der relativen Acidität der komplexbildenden Verbindung nimmt der Induktionseffekt der Nitril- oder Carbonylgruppe zu, was zur Erniedrigung der Elektronendichte am β-Kohlenstoffatom in der Vinylgruppe führt. Die Komplexbildung mit dem Monomeren verursacht auch eine erhöhte Delokalisierung der π-Elektronen in dessen Molekül. In Komplexen mit Lewis-Säuren mittlerer Stärke, zu denen z. B. CH3AlCl2, und C2H5AlCl2 gehören, ist wahrscheinlich die Delokalisierung der π-Elektronen am größten. Es wurde festgestellt, daß das durch C2H5AlCl2 komplexge-bundene Methylmethacrylat einen «Charge transfer»-Komplex mit 1,5-Cyclooctadien bildet. Auf Grund der Spektraluntersuchungen und der friiher erhaltenen Ergebnisse der Copolymerisation von Acryl-Monomeren mit Butadien wurde der Schluß gezogen, daß die Delokalisierung der π-Elektronen im komplexgebundenen Monomermolekül zu den wichtigsten, die Copolymerisationsgeschwindigkeit bestimmenden Faktoren gehört.
    Notes: Complexes of acrylonitrile and of methyl methacrylate with various Lewis acids, 1 and 2, were studied by means of IR, NMR, and UV spectroscopy. The influence of the Lewis acid strength on the induction effect and on the delocalization of π-electrons in the complexed monomer molecule was established. As the relative acidity of the complexing agent is increased, the inductive effect of the nitrile or of the carbonyl group in the complex molecule rises, whereby the electron density on the carbon atom in β-position in the vinyl group diminishes. Complexation of the monomer also results in increased delocalization of π-electrons in the molecule. In the complexes with moderately strong Lewis acids like CH3AlCl2 and C2H5AlCl2, delocalization of π-electrons seems to reach its maximum. The methyl methacrylate-C2H5AlCl2 complex was found to give a charge-transfer complex with 1,5-cyclooctadiene. On the basis of the present spectroscopic studies and of earlier studies on copolymerization of acryl monomers with butadiene, the delocalization of π-electrons in the complexed monomer molecule is believed to be one of the major factors controlling the rate of copolymerization.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1976.021770905
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