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  • 11
    ISSN: 1520-6041
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 111 (1989), S. 8754-8756 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 13
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 14
    ISSN: 1434-1948
    Keywords: Colloids ; Sol-gel processes ; Immobilization ; Heterogeneous catalysts ; Hydrogenations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A bimetallic, fully alloyed Pd/Au colloid of 3.0 nm particle size, obtained by the co-reduction of Pd and Au salts with tetraalkylammonium triethylhydroborate, was embedded in a silica matrix employing a modified sol-gel procedure with THF as the solvent. The removal of the protecting tenside led to a mesoporous texture with a comparatively narrow pore distribution. The physical characterisation by a combination of several techniques has shown that the SiO2-embedded Pd/Au colloid preserves the size and the structural characteristics of the colloidal metal precursor. The new material exhibits catalytic properties in selective hydrogenation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 15
    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
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  • 16
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 2447-2465 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: η1,η2-4-Alkenyl(η5-cyclopentadienyl)nickel Complexesη1,η2-4-Alkenylnickel complexes such as 1 isomerize at 70°C through a βH-elimination mechanism to give the corresponding η3-allylnickel compounds. Incorporation of the atoms C-1 and C-2 of the alkenyl ligand into an aromatic ring (in 10) or into a cyclopropyl system (in 11-17) increases the stability with respect to βH-elimination. 1H NMR investigations and a crystal structure determination (of 17) establish the molecular structure of 11-17. Reaction with PMe3 results in displacement of the C=C bond from nickel and formation of the 1:1 complexes 18-22. Analogous η1,η2-alkenyl compounds having chains one member shorter or longer are not stable: the 3-alkenyl compounds rearrange (dependent on the substituents at the C=C bond) to η3-cyclopentenyl (26) or to an open chain vinyl-substituted η3-allylnickel complex 28, while the 5-alkenylnickel system gives the hydrocarbons 29-31, the formation of which is discussed.
    Notes: η1,η2-4-Alkenylnickel-Komplexe wie 1 isomerisieren bei 70°C über einen βH-Eliminierungsmechanismus zu den entsprechenden isomeren η3-Allynickel-Komplexen wie z. B. 2, 3. Einbindung der Atome C-1 und C-2 des Alkenylliganden in einen aromatischen Ring in 10 oder in ein Cyclopropylsystem in 11-17 erhöht die Stabilität gegen βH-Eliminierung. 1H NMR- und Kristallstrukturuntersuchungen (an 17) beweisen die Molekülstruktur von 11-17. Durch PMe3 wird die C=C-Bindung aus der Koordination mit Ni verdrängt. Es entstehen die 1:1-Komplexe 18-22. Analoge η1, η2-Alkenylnickel-Verbindungen mit um ein Glied kürzerer oder längerer Kette sind nicht stabil. Die 3-Alkenylkomplexe lagern sich - abhängig von der Substitution an der C=C-Bindung - in den η3-Cyclopentenyl-Komplex 26 bzw. die offenkettige (η3-3-Vinylallyl)nickel-Verbindung 28 um. Aus 5-Alkenylnickel entstehen die Kohlenwasserstoffe 29-31, deren Bildung diskutiert wird.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 4248-4258 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 9,10-Dihydro-9,10-anthrylene Compounds of Aluminium„Anthracene magnesium“ and the 9,10-bis(trimethylsilyl) derivative 6 react with organoaluminium compounds in a number of different ways. The magnesium-μ-(9,10-dihydro-9,10-anthrylene)-aluminate complexes 1, 2, and 10 are formed in the reaction of „anthracene magnesium“ with R3Al (R = Me, Et) in toluene or with Et2AlOEt in THF. 6 reacts, in contrast, with Me3Al to give the 1:2 complex 7. The reaction of 1 with MeAlCl2 gives 9,10-bis(dimethylaluminio)-9,10-dihydroanthracene (3) or its THF adduct 4.6 reacts with Et2AlCl, depending on the molar ratio, to give either the chloromagnesium-aluminate 8 or the monomeric ethylaluminium compound 9. According to X-ray structure analyses, Mg and Al in 10 as well as both Al in 4 occupy axial positions in the 9,10-dihydro-9,10-anthrylene group. The Mg occupies a distored trigonal bipyramidal coordination with bonds to C-9, to the oxygen of the EtOAl group in 10, and to three THF molecules.
    Notes: „Anthracenmagnesium“ bzw. dessen 9,10-Bis(trimethylsilyl)-Derivat 6 reagieren in vielfältiger Weise mit Organoaluminium-Verbindungen. Die Umsetzung von „Anthracenmagnesium“ mit R3Al (R = Me, Et) in Toluol bzw. mit Et2AlOEt in THF ergibt die Magnesium-μ-(9,10-dihydro-9,10-anthrylen)-aluminat-Komplexe 1, 2 bzw. 10. Aus 6 und Me3Al entsteht dagegen der 1:2-Komplex 7. Die Reaktion von 1 mit MeAlCl2 führt zu 9,10-Bis(dimethylaluminio)-9,10-dihydroanthracen (3), das in den THF-Komplex 4 übergeführt werden kann. 6 reagiert mit Et2AlCl, abhängig vom Molverhältnis, entweder zum Chloromagnesiumaluminat-Komplex 8 oder zur monomeren Ethylaluminium-Verbindung 9. - Nach dem Ergebnis von Strukturanalysen besetzen in 10 Mg und Al, in 4 zwei Al axiale Positionen im 9,10-Dihydro-9,10-anthrylen-Rest. Das Mg ist durch Bindung an C-9, an den Sauerstoff der EtOAl-Gruppe in 10 sowie an drei THF verzerrt trigonal-bipyramidal koordiniert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 18
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Nickelocene with Organomagnesium Halides and Preparation of η3-Allyl-η5-cyclopentadienylnickel ComplexesNickelocene (1) reacts in ether/THF (ca. 5:1) with the 2-alkenylmagnesium compounds 2 - 5 and 11 in a molar ratio Ni/Mg - R = 1 to give the η3-allyl-η5-cyclopentadienylnickel complexes 6 - 9 and 12. Analogous compounds 14 - 19 are formed by the reaction of isopropyl- or isobutylmagnesium halide and 1,3-dienes with 1. Mixtures of isomeric allyl complexes are formed in the reaction of unsymmetrically substituted 1,3-dienes. The mixtures of syn-anti isomers equilibrate at 90°C. At 120°C an equilibration between the allylic isomers occurs.
    Notes: Nickelocen (1) reagiert in Ether/THF (ca. 5:1) mit den 2-Alkenylmagnesiumverbindungen 2 - 5 und 11 im Molverhältnis Ni/Mg - R = 1 glatt zu den η3-Allyl-η5-cyclopentadienylnickel-Komplexen 6 - 9 und 12. Analoge Verbindungen 14 - 19 entstehen bei gleichzeitiger Einwirkung von Isopropyl- oder Isobutylmagnesiumhalogeniden und 1,3-Dien auf 1. Mit unsymmetrisch substituierten 1,3-Dienen entstehen Mischungen isomerer Allylkomplexe, die beim Erhitzen auf 90°C in Gleichgewichtsgemische der syn-anti-Isomeren und bei 120°C in solche der Allyl-Isomeren übergehen.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
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  • 19
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 1455-1462 
    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
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