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  • 1995-1999  (46)
  • 1965-1969  (18)
  • 1900-1904  (1)
  • Chemistry  (62)
  • Tyr(P)-containing peptides  (3)
  • 1
    Electronic Resource
    Electronic Resource
    A small-angle x-ray scattering study of alginate solution and its Sol-Gel transition by addition of divalent cations (1995)
    New York : Wiley-Blackwell
    Biopolymers 35 (1995), S. 227-238 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The small-angle x-ray scattering (SAXS) technique has been applied to investigate solution and gel structures of alginate in the absence and presence of two divalent cations: Ca(II) and Cu(II). We have observed a broad maximum in the scattering curve, a characteristic of polyelectrolyte, for the purified alginate sample. The scattering maximum disappears in excess of added simple salt and shifts toward the higher angle region with increasing alginate concentration. Concentration dependence of the position and intensity of the maximum follows power law relations with exponents close to those predicted by theory. Data analysis shows an increase in correlation length ξ and cross-sectional diameter d0, of polymer chains upon gelation and suggests that a dimeric structure is adopted in the junction zone, consistent with the “egg-box” model previously proposed. In the Ca(II)-alginate system, the molecular parameters ξ and d0 are found to have good correlation with the macroscopic properties of gelation, such as gel point determined by viscosity measurements. However, for the Cu(II)-alginate system there is no clearly transitional behavior observed in ξ and d0, implying that the junction zone may be replaced by a more uniformly distributed site binding of Cu(II) ions to the carboxyl groups of both mannuronate and guluronate residues, in confirmation of previous 13C-nmr results. © 1995 John Wiley & Sons, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360350211
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Pteridine, XXXIII. Synthese und Struktur 8-substituierter Lumazine (1966)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 99 (1966), S. 3503-3523 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Verschiedene N-8-substituierte Lumazine werden synthetisch erhalten und durch ihre pK-Werte und UV-Absorptionsspektren charakterisiert. Die Neutralmoleküle und Monokationen zeigen übereinstimmende Strukturen, wogegen im alkalischen pH-Bereich unter normalen Bedingungen wenig übereinstimmende physikalische Daten erhalten werden. Kovalente Hydratation an das konjugierte System in 1.7-Stellung führt zu Gleichgewichtsgemischen verschiedener Molekülformen. Zur Klärung der Verhältnisse werden mit Hilfe einer Schnell-bestimmungsmethode die wahren pK-Werte und UV-Spektren der zum Teil instabilen Molekülformen bestimmt. Durch kinetische Messungen am 6.7.8-Trimethyl-lumazin (16) wird gezeigt, daß sich bei 6.7-Dimethyl-8-alkyl-lumazinen an die Wasseraddition noch eine reversible Ringöffnung des Pyrazinringes anschließt.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19660991117
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Crystal Smectic-B Phase from a Mesomorphic Ferrocene Derivative (1995)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 78 (1995), S. 1215-1218 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermal properties of two ferrocene derivatives, substituted by either one or two cholesteryloxycarbonyl units, were investigated. While the monosubstituted ferrocene derivative 1 was found to be non-mesomorphic, the disubstituted ferrocene derivative 2 exhibited a crystal smectic-B phase. This result shows that ferrocene-containing thermotropic liquid crystals, despite the bulkiness of the metallocene core, are not limited to disordered calamitic phases.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19950780514
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  • 4
    Electronic Resource
    Electronic Resource
    Supermolecules Containing a Tetrahedral Core: A New Class of Liquid-Crystalline Siloxanes (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 521-525 
    Details
    ISSN: 0009-2940
    Keywords: Liquid crystals ; Siloxanes ; Phase behaviors ; Defined topology ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that supermolecules with a tetrahedral symmetry and appropriate side-chains exhibit liquid-crystalline phase behaviour. The use of an optimised hydrosylation reaction allows for the synthesis of materials that have four mesogenic groups attached to a siloxane core, where the conformation and the configuration are unambiguous. The materials show low glass transition temperatures and, depending on the spacer length, complex liquid-crystalline morphologies.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290508
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  • 5
    Electronic Resource
    Electronic Resource
    Bor-Stickstoff-Verbindungen, XIX: Einige neue Aminoborane (1965)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 98 (1965), S. 3050-3052 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Im Zuge der Darstellung einiger neuer Aminoborane wird bei der Grignard-Reaktion von Dihalogenaminoboran, R2N—BX2, ein Halogenorganoaminoboran, R2N—BXR′, erhalten. Die Spaltung einer B—C-Bindung durch Triäthylsilylamin während einer Transaminierungsreaktion wird beschrieben.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19650980938
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  • 6
    Electronic Resource
    Electronic Resource
    Bor-Stickstoff-Verbindungen, XXVIII. Reaktionen von Aminoboranen mit Schwefel-Verbindungen (1967)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 100 (1967), S. 1898-1901 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Umsetzung von Aminoboranen mit Dithioglykolen ergibt Amin-Addukte des Typs 4 von 1.3-Dithia-2-bora-cycloalkanen (z. B. von 1). Ebenso entstehen bei der Reaktion von Amino-boranen mit o-Amino-thiophenol heterocyclische Verbindungen, z. B. 5 und 6 Hepta-schwefelimid und S4(NH)4 reagieren dagegen nicht mit Aminoboranen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19671000616
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  • 7
    Electronic Resource
    Electronic Resource
    Pteridine, XXXIV. Synthese und Struktur 8-substituierter Pterine (1968)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 101 (1968), S. 1072-1088 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bestimmte Molekülformen der 8-substituierten Pterine unterliegen einer kovalenten Hydratation. Die Kationen sowie sämtliche Neutralmoleküle, die aus Valenzgründen die Ausbildung einer 2-Aminofunktion zulassen, existieren in der wasserfreien Form. Das Auftreten einer exocyclischen Iminogruppe führt zu einer instabilen Molekülform, die sofort kovalent hydratisiert wird. Die Anionen leiten sich von den kovalenten Hydraten ab, deren Beständigkeit zusätzlich von den Substituenten in 6- und 7-Stellung abhängt. Während die 6.7-H- und 6.7-Diphenyl-Derivate lediglich einer nucleophilen OH-Addition unterliegen, zeigen die 6.7-Dimethyl-Verbindungen als Folgereaktion eine Ringöffnung des Pyrazinringes. Zur Klärung der komplexen Verhältnisse werden die instabilen Molekülformen mit Hilfe einer Schnellbestimmungsmethode erfaßt. NMR-Untersuchungen und kinetische Messungen bestätigen die kovalente Hydratation. Sie ist reversibel und wird durch Hydronium- und Hydroxyl-Ionen katalysiert. Die Ringöffnungs- und Cyclisierungsreaktionen der 8-subst. 6.7-Dimethyl-pterine zeigen dagegen eine Pufferkatalyse, die als Charakteristikum zur Entscheidung der erfolgten Reaktion herangezogen werden kann.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19681010344
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  • 8
    Electronic Resource
    Electronic Resource
    Bis[4(1-methyl-1,2-epoxyethyl)] derivatives of phenyl ether, 1,4-diphenoxybenzene, and bis(4-phenoxyphenyl) etherProd. No. 1615 (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 2029-2036 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The syntheses of three new α-methyl-substituted bis(epoxyethyl) derivatives of phenyl ether, 1,4-diphenoxybenzene, and bis(4-phenoxyphenyl) ether are reported. Improved procedures for preparing 1,4-diphenoxybenzene and bis(4-phenoxyphenyl) ether by the Ullmann method are described. Infrared spectral data for the bisepoxides and their precursors are given, as are some reactions of the bisepoxides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1967.070111019
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  • 9
    Electronic Resource
    Electronic Resource
    Novel thermally stable and chemically resistant epoxy polymers derived from phenylene oxides (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 607-618 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Thermogravimetric and differential thermal analysis data are presented for three novel bisepoxy monomers and formulated coatings derived therefrom. The coatings were insensitive to impact in liquid oxygen and showed excellent resistance to liquid nitrogen tetroxide, concentrated nitric acid, and a variety of organic solvents. All coatings showed excellent adhesion to metals and oxidation resistance superior to any known commercial epoxy polymer. Thermal resistance was excellent at 500°F. for periods of at least 500 hr. in air. Other data on these novel epoxy polymers are also presented.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120401
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  • 10
    Electronic Resource
    Electronic Resource
    Polyamides incorporating phosphine oxide groups. III. Polymerisation of bis[4-(2-aminoethyl)aminophenyl]-phenylphosphine oxide with dicarboxylic acids (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 2865-2870 
    Details
    ISSN: 0887-624X
    Keywords: phosphine oxide ; aromatic-aliphatic polyamides ; polycondensation ; thermal properties ; fire retardant materials ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The new polymerisation monomer bis[4-(2-aminoethyl)aminophenyl]-phenylphosphine oxide (p-BAPPO) was prepared in good yield by the nucleophilic substitution reaction between bis(4-fluorophenyl)phenylphosphine oxide and a large excess of 1,2-diaminoethane. Five novel polyamides, incorporating phosphine oxide groups within the polymer backbone were synthesised by the condensation reaction of p-BAPPO with a series of aromatic and aliphatic dicarboxylic acids. The thermal properties of these polymers were investigated by differential scanning calorimetry and thermogravimetric analysis. Glass transition temperatures in the 180-215°C range were recorded. Although we observed their thermooxidative stabilities (5% weight loss 〉 345°C) to be lower by 40-70°C than those previously found for wholly aromatic polyamides with phosphine oxide groups within the parent chain, char yields upon prolonged heating at 650°C were still excellent (26-38%). Also, good solubility in aprotic polar solvents was observed for all polyamides synthesised. The new polyamides clearly represent significant progress in the quest for processible fire retardant materials. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2865-2870, 1997
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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