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  • 1
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complex Chemistry of Reactive Organic Compounds, XXIV. Five-Membered Cobalta Cycles from Carbene Addition to Dicarbonyl (η5-cyclopentadienyl)cobaltPhotolysis of the dialkyl diazomalonates 2a-g in the presence of dicarbonyl(η5-cyclopentadienyl)cobalt (1) in tetrahydrofuran yields the cobalta cycles 3a-g. The formation of the new compounds, established by X-ray structural determination on the case of 3c, can be explained formally as a result of a [2 + 3]-cycloaddition of the carbenes derived from the diazo precursors 2a-g to the organometallic substrate 1. The cyclic cobalt compounds 3a-g are converted by a thermal reaction with 1 through opening of the metalla cyclic structural element into the dinuclear μ-methylene cobalt compounds 4a-g.
    Notes: Durch Photolyse der Diazomalonsäure-dialkylester 2a-g in Gegenwart von Dicarbonyl-(η5-cyclopentadienyl)cobalt (1) in Tetrahydrofuran sind die Cobaltacyclen 3a-g zugänglich. Die Bildung der neuen, am Beispiel von 3c auch röntgenstrukturanalytisch gesicherten Verbindungen ist formal das Ergebnis einer [2 + 3]-Cycloaddition der von den Diazo-Vorstufen 2a-g abgeleiteten Carbene an das Organometall-Substrat 1. Unter Öffnung des metallacyclischen Strukturelements sind die cyclischen Cobalt-Derivate 3a-g bei thermischer Umsetzung mit 1 in die zweikernigen μ-Methylen-Cobalt-Komplexe 4a-g überführbar.
    Additional Material: 1 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 508 (1984), S. 100-106 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complex Chemistry of Reactive Organic Compounds. XLV. Organometallic Methanediazo Complexes: Protonation and CycloadditionThe reactions of the methanediazo tungsten complex (η5-C5H5)W(CO)2(N2CH3) (1) with protic acids are strongly governed by solvent effects: while trifluoromethylsulfonic acid induces clean protonation with formation of the ionic derivative [(η5-C5H5)W(CO)2(HN2CH3)]+CF3SO3- (3) when diethylether is used as a solvent, compound 4 is formed in the presence of acetonitril which latter solvent has good coordination capabilities itself. Compound 4 originates from a novel type of cycloaddition reaction in which the protonated species of composition [(η5-C5H5)W(CO)(CH3CN)(HN2-CH3)]+CF3SO3- is involved. Complete elimination of the nitrogeneous ligand ensemble with concomitant formation of the halogen complex (η5-C5H5)W(CO)2Br3 (5) occurs upon treatment of 1 with hydrogen bromide.
    Notes: Stark ausgeprägte Solvens-Effekte beeinflussen die Säure-Reaktionen des Methandiazo-Wolfram-Komplexes (η5-C5H5)W(CO)2(N2CH3) (1): Während Trifluormethansulfonsäure in Diethylether die glatte Protonierung zum salzartigen Derivat [(η5-C5H5)W(CO)2(HN2CH3)]+CF3SO3- (3) bewirkt, bildet sich im koordinationsfähigen Lösungsmittel Acetonitril die Verbindung 4, die durch eine neuartige Cycloaddition eines Solvens-Moleküls an die protonierte Spezies [(η5-C5H5)-W(CO)(CH3CN)(HN2CH3)]+CF3SO3- zustandekommt. Mit Bromwasserstoff erfolgt vollständige Abspaltung des stickstoffhaltigen Ligandensembles zum Halogeno-Komplex (η5-C5H5)W(CO)2Br3 (5).
    Additional Material: 2 Tab.
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  • 3
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Übergangsmetall-Methylen-Komplexe, VII Studien über Metall-Metall-Bindungen, V. Darstellung und Molekülstruktur eines Carbonylcobalt-Komplexes mit einem neuartigen carbocyclischen μ-Methylen-LigandenDicarbonyl(η5-cyclopentadienyl)cobalt (1) reagiert mit 2-Diazo-1,3-dioxoindan (2) unter thermischen Bedingungen (siedendes Benzol) unter Bildung des zweikernigen Cobalt-Komplexes 3, der das von 2 abgeleitete Carben als Brückenliganden enthält. Eine Röntgenstrukturanalyse wies nach, daß die beiden Cyclopentadienyl-Ringe ebenso wie die beiden Carbonyl-Gruppen trans-Positionen zueinander einnehmen. Trotz seiner vier Bindungspartner weist das Methylen-Kohlenstoffatom eine sehr stark verzerrte tetraedrische Konfiguration auf [∢Co(1)—C(3)—Co(2): 79.0(1)°, ∢C(4)—C(3)—C(11): 104.3(3)°]. Der Cobalt-Cobalt-Abstand beträgt 247.5(1) pm; die Abstände und Winkel der Co—C(C5H5)- sowie Co—C(CO)-Bausteine sind normal. Das μ-1,3-Dioxoindan-2-yliden-Gerüst ist entlang der Verbindungslinie zwischen den beiden Carbonyl-Kohlenstoffatomen des Dion-Systems um 2° abgewinkelt.
    Notes: Dicarbonyl(η5-cyclopentadienyl)cobalt (1) reacts with 2-diazo-1,3-dioxoindane (2) under thermal conditions (boiling benzene) to yield the dinuclear cobalt complex 3 which contains the carbene derived from 2 as a bridging ligand. An x-ray diffraction study proved that both the cyclopenta-dienyl rings are oriented trans to each other, which is also true for the two metal-carbonyl groups. While four-bonded, the methylene carbon is highly distorted from tetrahedral geometry [∢Co(1)—C(3)—Co(2): 79.0(1)°, ∢C(4)—C(3)—C(11): 104.3(3)°]. The cobalt  -  cobalt distance is 247.5(1) pm and the Co—C(C5H5) and Co—C(CO) distances and angles are normal. The μ-1,3-dioxoindane-2-ylidene backbone is bent by 2° along the vector joining the two carbonyl carbon atoms of the dione system.
    Additional Material: 2 Ill.
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  • 4
    Publication Date: 1984-01-01
    Print ISSN: 0044-2313
    Electronic ISSN: 1521-3749
    Topics: Chemistry and Pharmacology
    Published by Wiley
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