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  • Chemistry  (3)
  • Benzocyclobutenedione complexes  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Reactions of benzocyclobutene chromium complexes with carbon, nitrogen and oxygen nucleophiles: nucleophilic addition and unexpected proximal ring opening reactions
    Amsterdam : Elsevier
    Inorganica Chimica Acta 220 (1994), S. 175-186 
    Details
    ISSN: 0020-1693
    Keywords: Benzocyclobutenedione complexes ; Benzocyclobutenone complexes ; Chromium complexes ; Crystal structures ; Ring opening
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0020-1693(94)03870-8
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  • 2
    Electronic Resource
    Electronic Resource
    Polyurethane cationomers with pendant trialkylammonium groups: Effects of ion content, alkyl group, and neutralizing anion (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 32 (1994), S. 1557-1571 
    Details
    ISSN: 0887-6266
    Keywords: polyurethanes ; cationomers ; morphology ; thermal properties ; tensile properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Diphenylmethane-4,4′-diisocyanate based polyether polyurethane cationomers were synthesized using 3-trialkylammonium-(1,2-propanediol)iodide (TAPI) as the chain extender. The ionic content was varied by substituting up to 100% of 3-dialkylamino-1,2-propanediol (DAP) for TAPI. Cationomers with bromine and chlorine ions were prepared from the iodine-based polymer via ion exchange. The morphology and properties of the cationomers were studied as a function of alkyl group, ion content, and anion type using small-angle x-ray scattering, tensile testing, dynamic mechanical thermal analysis, and differential scanning calorimetry. The bulky side groups of DAP and TAPI prevented crystallization in the hard domains, and consequently little or no phase separation was evident in the unionized materials. Polyurethanes with cationic functionality showed dramatic improvements in phase separation and tensile properties. Results suggest tht while ionic interactions are the primary driving force for phase separation, they produce a morphology not typical of ionomers, but rather akin to that of a conventional polyurethane with semicrystalline hard segments. © 1994 John Wiley & Sons, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1994.090320827
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  • 3
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetallkomplexen, 8. Untersuchungen zur Synthese ungesättigter δ-Lactone durch Cyclocarbonylierung von Vinyloxiranen mit Übergangsmetall-Komplexen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3644-3671 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organic Syntheses by Means of Transition Metal Complexes, 8 - Synthesis of Unsaturated δ-L-Lactones from Vinyloxiranes and Carbon Monoxide via Transition Metal ComplexesThe transition metal-assisted carbonylation of vinyloxiranes to unsaturated δ-lactones has been verified and studied mechanistically by use of organometallic model reactions. The light induced complexation of vinyloxiranes 1 by Fe(CO)5 was shown to be a multistep reaction in which diastereomeric cis-resp. trans- ferralactones 2 are formed. Complexes of both types (2k, 2k′) were characterized crystallographically and studied chemically concerning their reactions with nucleophiles and electrophiles. Reaction with primary amines gives ferralactames 7 by migration of the allyl group and inversion at C-1 as well as C-4 indicating an attack of amine at the exo-position of C-4. On the other hand the reaction with HO⊖ leads to the formation of CO23⊝ and diene complexes 10 with inversion at C-1 only, indicating that the reaction has been initiated by attack of HO⊖ at a terminal carbonyl group. On electrophilic attack ferralactones form allyl cations (14, 16) by opening of the CO - O bond. Carbonylation of ferralactones with CO in aprotic solvents give good yields of unsaturated δ-lactones (12). In the case of isoprene epoxide it has been shown that homogeneous catalytic cyclocarbonylation of vinyloxiranes can be of synthetic use.
    Notes: Anhand metallorganischer Modellreaktionen wurde die Cyclocarbonylierung von Vinyloxiranen zu ungesättigten δ-Lactonen untersucht. Die photochemisch initiierte Komplexierung von Vinyloxiranen 1 (X = O) an Fe(CO)5 verläuft mehrstufig und führt zu diastereomeren cis- bzw. trans-Ferralactonen 2. Vertreter beider Verbindungstypen (2k, 2 k′) wurden kristallographisch charakterisiert und chemisch bezüglich ihres Verhaltens gegenüber Nucleophilen und Elektrophilen studiert. Mit primären Aminen bilden sich Ferralactame 7 unter Wanderung des Allylsystems sowie unter Konfigurationsumkehr an C-1 und C-4, was den exo-Angriff des Amins an C-4 des Allylsystems beweist. Bei Einwirkung von HO⊝ hingegen zerfallen Ferralactone zu CO23⊝ und Dien-komplexen 10, wobei lediglich an C-1 eine Konfigurationsumkehr beobachtet wird. In diesem Fall greift HO⊝ somit an einer terminalen Carbonylgruppe an. Elektrophile bewirken die Spaltung der CO-O-Bindung unter Bildung von Allyl-Kationen (14, 16). Die Carbonylierung von Ferralactonen führt in aprotischen Lösungsmitteln in guten Ausbeuten zu ungesättigten S-Lactonen (12). Am Isoprenepoxid wurde gezeigt, daß auch die homogenkatalytische Cyclocarbonylierung von Vinyloxiranen gute Ausbeuten an δ-Lactonen ergibt und dieses Verfahren für Synthesen von Interesse ist.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791121114
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  • 4
    Electronic Resource
    Electronic Resource
    H—C-Bindungsspaltungen bei Aldehyden durch Neopentylruthenium(II)-KomplexeProfessor Rudolf Taube zum 60. Geburtstage gewidmet (1991)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 606 (1991), S. 141-155 
    Details
    ISSN: 0044-2313
    Keywords: Neopentylruthenium(II) complexes ; H—C bond cleavage ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: H—C Bond Cleavage in Aldehydes by Neopentylruthenium(II) ComplexesNeopentylruthenium complexes of the type (η5-Cp)(L1)(L2)RuCH2CMe3 (1: Cp = C5Me5, L1 = L2 = PMe3; 3, 9, 10 and 11: Cp = C5H5, L2 = PPh3, L1 = PMe3, PMePh2, PMe2Ph and P(OMe)3, respectively) react with benzaldehyde with H—C bond cleavage of the aldehyde function to give the (η5-Cp)(L1)(L2)Ru benzoyl compounds 4, 13-16 and as the result of subsequent decarbonylation the (carbonyl) phenylruthenium complexes 2, 5, 12, 17-19 or mixtures thereof. Para phthaldialdehyde reacts with 1 (ratio 1 : 2) via the carbonyl complex 20 to give the 1,4-bis(ruthenium)benzene compound 21. Aliphatic aldehydes behave similarly: isobutyraldehyde reacts with 3 to give a mixture of the acyl-(22) and alkyl(carbonyl)ruthenium compound 23. 1 reacts with ferrocenealdehyde to give the carbonyl(ferrocenyl)ruthenium complex 25. The molecular structures of 22 and 2 as representatives of acyl- and (carbonyl)organylruthenium complexes, have been determined by X-ray diffraction.
    Notes: Die Neopentylruthenium-Komplexe vom Typ (η5-Cp)(L1)(L2)RuCH2CMe3 (1: Cp = C5Me5, L1 = L2 = PMe3; 3, 9, 10 und 11: Cp = C5H5, L2 = PPh3, L1 = PMe3, PMePh2, PMe2Ph bzw. P(OMe)3) reagieren mit Benzaldehyd unter H—C-Bindungsspaltung an der Aldehydgruppe und anschließender Decarbonylierung zu den entsprechenden Phenylruthenium-Verbindungen (η5-Cp)(CO)(L1)RuPh 2, 5, 12, 17-19 oder zu Mischungen dieser Komplexe mit den Benzoylruthenium-Verbindungen (η5-Cp)(L1)(L2)RuC(O)Ph 4, 13-16, den Vorstufen der Decarbonylierung. Para-Phthaldialdehyd reagiert mit 1 (Verhältnis 1 : 2) über den Carbonylkomplex 20 zum 1,4-Bis(ruthenium)benzol 21. Aliphatische Aldehyde verhalten sich ähnlich wie aromatische, Isobutyraldehyd bildet mit 3 eine Mischung von Acyl- (22) und Alkyl(carbonyl)ruthenium-Verbindung 23. 1 reagiert mit Ferrocenaldehyd zum Carbonyl(ferrocenyl)ruthenium-Komplex 25. Für 22 und 2 als Vertreter der Acyl- und der (Carbonyl)phenylruthenium-Komplexe wurden die Molekülstrukturen röntgenographisch bestimmt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19916060115
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