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  • 1
    Electronic Resource
    Electronic Resource
    Highly Substituted Cyclams: Stereoselective Synthesis and Coordination Properties (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 521-528 
    Details
    ISSN: 0009-2940
    Keywords: Macrocycles ; Hydrogenation ; Cyclam, binding constant ; N ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We report here a new synthetic route to highly-substituted tetraazamacrocycles. Raney nickel hydrogenation of macrocyclic phenylenediamine-acetylacetone condensation products gives cyclams in high yield with complexes all-cis stereoselectivity. The extensive C-substitution of the cyclam 2a changes its ligand properties markedly. The X-ray structure analyses of NiII, CuII, and ZnII complexes of 2a reveals a deviation of the metal ion coordination geometry from the usual square-planar arrangement. This may account for the differences in the redox properties of the NiII and CuII complexes of 2a leads to more positive oxidation and reduction potentials compared to the analogous unsubstituted cyclam complexes. While the binding constant between Zn(ClO4)2 and 2a is lower by a factor of 105 compared to cyclam, the subsequent binding of uridine to the zinc-cyclam complexes in methanol/water is slightly stronger in the case of 2a · Zn(ClO4)2].
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300412
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  • 2
    Electronic Resource
    Electronic Resource
    Wissenschaft aktuell (1997)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 31 (1997), S. 37-41 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die rote Farbe des kolloidalen Goldes war schon den Alchimisten des Mittelalters bekannt. 1663 beschreibt der Leidener Arzt Andreas Cassius die Färbung von Glas und Porzellan mit Hilfe von Goldverbindungen. Aber auch in jüngster Zeit sind Darstellung und Eigenschaften ultrakleiner Goldteilchen noch ein hochaktuelles Thema. Ein Beispiel sind die von G. Schmid beschriebenen ligandenstabilisierten Goldcluster [1]. Abhängig von der Struktur der Liganden (Thiole, Phosphane, etc.) gelingt es, vor allem kuboktaedrische „Full-shell-Cluster“ aus 13, 55, 147, 309, 561 Goldatomen (die sogenannten magischen Zahlen) in hoher Reinheit zu isolieren.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19970310108
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  • 3
    Electronic Resource
    Electronic Resource
    Photochemical and Thermal Cycloaddition Reactions of 3-Thioxoandrosta-1,4-dien-17-one with Electron-Deficient Alkynes (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 2347-2349 
    Details
    ISSN: 0947-3440
    Keywords: 3-Thioxoandrosta-1,4-dien-17-one ; Cycloaddition reactions ; Steroids ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 3-Thioxoandrosta-1,4-dien-17-one (4) reacts with acetylene dicarboxylic acid esters to form novel spiro compounds of the thiine type (6a, 6b), whereas with free acids, such as acetylene dicarboxylic acid and propiolic acid, the spirocyclic O,S-acetals 7a and 7b are obtained. This study demonstrates that the cycloaddition reaction is promoted by photochemical and also thermal activation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719971124
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  • 4
    Electronic Resource
    Electronic Resource
    Configurational assignment of optically active hydroperoxy homoallylic alcohols and the corresponding diols by circular dichroism and multidimensional gas chromatography (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 9 (1997), S. 69-74 
    Details
    ISSN: 0899-0042
    Keywords: diols ; hydroperoxides ; absolute configuration ; exciton coupling ; circular dichroism ; enantiomeric separation ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Allylic hydroperoxides are a class of compounds of versatile synthetic utility. Optically active diastereomeric hydroperoxy homoallylic alcohols and their corresponding diols are easily available through horseradish peroxidase (HRP)-catalyzed kinetic resolution of racemic hydroperoxides. Here we describe the assignment of the absolute configuration of the optically active products and substrates obtained after HRP-catalysis by the circular dichroism exciton chirality method. Moreover, the analytical-scale separation of the enantiomers based on multidimensional gas chromatography on chiral columns is presented. Since the enantiomeric elution order on the ciral columns was constituted, the absolute stereochemistry of optically active allylic diols can easily be deduced by their retention times on β-cyclodextrins. Chirality 9:69-74, 1997. © 1997 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of monomethacrylate-functionalized self-organizing crown ether compounds (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 198 (1997), S. 265-277 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Synthesis and characterization of methacrylate-monofunctionalized crown ether compounds based on derivatives of 2-hydroxymethyl-1,4,7,10,13-pentaoxacyclopentadecane and 4′-hydroxymethyl-1,4,7,10,13-pentaoxabenzocyclopentadecane is described. By differential scanning calorimetry (DSC) and thermooptical analysis (TOA) it is shown that the synthesized compounds and their sodium triflate complexes exhibit columnar mesophases.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1997.021980204
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  • 6
    Electronic Resource
    Electronic Resource
    Novel benzo-15-crown-5 functionalized α-olefin/CO terpolymers for membrane applications (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 198 (1997), S. 2759-2768 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The synthesis of a benzo-15-crown-5 functionalized α-olefin (4′-(undec-10-enylcarboxylate)benzo-15-crown-5, 5) and its terpolymerization with carbon monoxide and various α-olefins are described. A decline of the glass transition temperatures (Tg) of the corresponding terpolymers was observed upon incorporating compound 5 into the polymer main chain. Ion-selective membranes were prepared by encapsulating the benzo-15-crown-5 functionalized α-olefin/CO terpolymers in a microporous polyethylene support. Preliminary ion-transport experiments demonstrate the ability of these novel crown ether substituted polyketones to transport NaClO4 across the membranes. Adjusting the polarity of the polyketones via the length of the olefinic side chain offers a means to control the ion-permeation-rates.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1997.021980908
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  • 7
    Electronic Resource
    Electronic Resource
    Semifluorinated diblock copolymers. Synthesis, characterisation and amphiphilic properties (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 198 (1997), S. 2163-2179 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Semifluorinated diblock copolymers based on methyl methacrylate and 1H,1H,2H,2H-perfluoroalkyl methacrylates were prepared by nucleophilic catalysed group transfer polymerisation. Characterisation was carried out by 1H NMR spectroscopy, differential scanning calorimetry (DSC) and gel-permeation chromatography (GPC) in toluene. The latter method revealed the formation of micelles. The surface activity of the materials was demonstrated by tensiometry using a Wilhelmy balance. Measurements on thin polymer films showed low critical surface tensions and low dispersion force contributions to the surface energy indicating the presence of the fluorinated block at the surface.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1997.021980714
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  • 8
    Electronic Resource
    Electronic Resource
    Self-organization of a liquid crystalline methacrylate-monofunctionalized crown-ether compound in low-shrinkage acrylate mixtures (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 198 (1997), S. 2839-2852 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Crystallization and supramolecular aggregation of 1,4,7,10,13-pentaoxacyclopentadecane-2-ylmethyl 3,4-bis[4-(dodecyl-1-oxy)benzyloxy]-5-(11-methacryloyloxyundecyl-1-oxy)benzoate (1) and its complexes with sodium triflate are described in solutions of the methacrylate monomers. Formation of a gel was observed covering a rather wide concentration range in the pseudo-binary phase diagram. In the low concentration regime and at low temperatures, gel formation by elongated crystals of 1 was observed. It was demonstrated that the formation of a crystalline network and the shape of the crystals strongly depend on the cooling rate.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1997.021980914
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  • 9
    Electronic Resource
    Electronic Resource
    Polymerization of cyclotrisiloxanes by organolithium compounds and P2-Et baseSystematic name: 1-ethyl-2,2,4,4,4-pentakis(dimethylamino)-2γ5,4γ5-catenadiphosphazene. (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 198 (1997), S. 717-726 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The use of the phosphazene base P2-Et(a) as a promoter for the anionic polymerization of hexamethylcyclotrisiloxane (D3Me) or hexaethylcyclotrisiloxane (D3Et) initiated by an organolithium compound leads to well-defined polysiloxanes. At low conversion (〈 ca. 9%) the polymerization of D3Me behaves like a living polymerization, however, polymers with a narrow molecular weight distribution (M̄w/M̄n 〈 1.1) are obtained up to much higher conversions (ca. 70%). Kinetic data and NMR spectroscopy revealed the existence of a dynamic equilibrium between complexed and uncomplexed lithium silanolates. Below ambient temperature several different types of aggregates were indicated. The occurrence of an acceleration was observed after ca. 9% conversion.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1997.021980304
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  • 10
    Electronic Resource
    Electronic Resource
    Molekulardynamische Simulationen in der Thermo- und Fluiddynamik (1997)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 69 (1997), S. 1285-1285 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.3306909107
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