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  • 1
    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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  • 2
    Electronic Resource
    Electronic Resource
    Verschiedenartige Koordinationen bei η2-Alken)-(η5-cyclopentadienyl)organylnickel(II)-Komplexen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 441-452 
    Details
    ISSN: 0009-2940
    Keywords: (η2-Alkene)(η5-cyclopentadienyl)organylnickel(II) complexes, stability and reactivity of ; Cyclopentadienyl ligands, substituted ; Chelating alkenylcyclopentadienyl ; Nickel complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Various Coordinations in (η2-Alkene)(η5-cyclopentadienyl)organylnickel(II) ComplexesA series of (η2-alkene)(η5-cyclopentadienyl)organylnickel(II) complexes with substituted cyclopentadienyl ligands is synthesized in order to compare the structures, the thermal stabilities, and chemical reactivities. In (allyl)(η5-Cp')Ni compounds the allyl moiety is η3-coordinated when Cp'=C5H5, C5Me5 (1), C5Ph5 (2), indenyl (3), [Hydridotri(pyrazolyl)borato] (4) (as an equivalent of the cyclopentadienyl ligand), and [C5H4((CH2)3CH=CH2)] (22). It is found that the [(η2-alkene)alkyl(η5-Cp')nickel] compounds [Cp'=C5Me5; alkene=C2H4, alkyl=Me (10), Et (9) or alkene=(1 - 2-η2)-1,3-butadiene, alkyl=Me (11); Cp'=C5Ph5; alkene=C2H4, alkyl=Me (12)] are thermally more stable and less reactive than their η5;- C5H5 analogues; the largest increase in thermal stability is observed when the η5-Cp' and the η2-alkene functions are connected by substitution of the cyclopentadienyl ligand with an alkenyl group of suitable chain length. In the case of compounds of the general type [(η5-C5R4((CH2)nCH=CH2))-(ligand)Ni(II)] with Ph3P as the ligand these complexes are cationic [R=H, n=3 (14+) or R=Me, n=2 (17+)]. On the other hand, the compounds with anionic ligands are neutral complexes (R=H, n=3, ligand=methyl (19), ethyl (20), isopropyl (21) or R=Me, n=3 and ligand=iodide (24), bromide (25), methyl (26), ethyl (27)]. In 14+, 17+, 19 - 21 and 24 - 27 the C=C bond of the alkenyl group is η2-coordinated to the nickel atom. X-ray structures have been determined for 4 and 25.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240306
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  • 3
    Electronic Resource
    Electronic Resource
    (ν5-Cyclopentadienyl)methylnickel-Komplexe mit Ein- und Mehrfach-Doppelbindungssystemen (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2542-2552 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (ν5-Cyclopentadienyl)methylnickel Complexes with Single and Multiple Double-Bond SystemsThe reaction of nickelocene (1) with methyllithium in the presence of a variety of olefins has been studied and complexes have been isolated involving 1-alkenes (4), olefins with internal double bonds (2, 3), α,ω-alkadienes (5), as well as cycloalkenes (6) and the cycloalkapolyenes with six- (7, 8), eight- (9), and twelve-membered rings (10-12). Single complexation is generally observed also when more than one C=C bond is present. In the case of 1,3-cyclohexadiene an additional complex is formed in which each C=C bond is coordinated to a CpNi-methyl moiety, and in the case of 1,5-cyclooctadiene this is the only type of complex isolated (13,14). Thermolysis of the ν2-1,3-alkadiene compounds 15-17 results in elimination of ethane to give the binuclear (CpNi)2 -ν4-alkadiene complexes 18-20.
    Notes: (ν5-Cp)methylnickel-Komplexe mit verschiedenartigen C=C-Bindungssystemen in 1-Alkenen (4), in Olefinen mit interner Doppelbindung (2, 3), α,ω-Alkadienen (5) sowie in Cycloalkenen (6) und Cycloalkapolyenen sechs- (7, 8), acht- (9) und zwölfgliedriger Ringe (10-12) wurden durch Umsetzung von Nickelocen (1) mit Methyllithium in Gegenwart dieser Olefine erhalten. Olefine mit mehreren C=C-Bindungen sind im Normalfall nur einfach komplexiert. Bei 1,3-Cyclohexadien werden zusätzlich, bei 1,5-Cyclooctadien ausschließlich die Komplexe 13, 14 erhalten, bei denen an jede C=C-Bindung ein CpNi-methyl koordiniert ist. Thermolyse der ν2-1,3-Alkadien-Verbindungen 15-17 führt unter Ethan-abspaltung zu zweikernigen (CpNi)2-ν4-Alkadien-Komplexen 18-20.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190813
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