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  • 1
    Electronic Resource
    Electronic Resource
    Optische Rotationsdispersion und Circulardichroismus bei Jod-Polysaccharid-Komplexen (1968)
    Springer
    Colloid & polymer science 227 (1968), S. 65-72 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Summary Aqueous solutions of iodine complexes with starch, different samples of amylose or amylopectin show an induced positive Cotton effect in the region of the absorption maximum. The rotatory power and the extinction at 660 and 445 mμ depends upon iodine amylose ratio. The optical of some complexes increases with time, whereas the absorption remains constant. Experimental conditions which change the structure of the channel complexe (heating, addition of salts, solvents, urea or detergents) influence the induced Cotton effect.
    Notes: Zusammenfassung Die wäßrigen Lösungen der Jodkomplexe von Stärke, verschiedenen Amylosen und Amylopektinen zeigen im Bereich der betreffenden Absorptionsmaxima einen induzierten positiven Cotton-Effekt. Die Drehwerte hängen in der gleichen Weise vom Jod-Amylose-Verhältnis ab wie die Extinktionen bei 660 und 445 mμ. Die Drehwerte einiger Jod-Polysaccharid-Komplexe nehmen mit der Zeit stark zu, obwohl die Extinktion konstant bleibt. Maßnahmen, durch welche die Struktur der Jod-Einschlußverbindung verändert wird (Erwärmung, Zusatz von Salzen, Lösungsmitteln, Harnstoff, Netzmitteln) haben einen starken Einfluß auf den induzierten Cotton-Effekt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02085280
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  • 2
    Electronic Resource
    Electronic Resource
    Asymmetrische Reduktion von PolyvinylacetophenonTeil der Dissertation von H. Mayerhöfer, Mainz D 77. (1968)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 80 (1968), S. 236-237 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19680800610
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  • 3
    Electronic Resource
    Electronic Resource
    Conformation of amylose in aqueous solution: Optical rotatory dispersion and circular dichroism of amylose-iodine complexes and dependence on chain length of retrogradation of amylose (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 243-261 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dependence on chain length of two characteristic properties of amylose, i.e., retrogradation and complex formation with iodine, have been studied by using enzymatically synthesized, homodisperse amyloses. The association rates of amyloses in water containing 5% dimethyl sulfoxide have a sharp maximum at a degree of polymerization P̄n of 80; shorter and longer molecules are much more soluble. The iodine complexes of amylose exhibit a strong Cotton effect in the range of the long-wave absorption maximum (position depending on chain length) and two weaker Cotton effects at 480 and 350 nm. The long-wave Cotton effect is most intense at about P̄n 50 and decreases rapidly for shorter and longer chains. This behavior is unexpected and is not in accordance with the further increase of λmax and λmax. The experiments can best be interpreted by assuming well ordered, stiff chains in the low molecular weight range (P̄n 50-80). For longer chains, the findings are discussed in the light of current concepts of amylose conformation in aqueous solution, namely the model of the broken helical chain (alternating stiff helical segments and unordered regions) and the model of a flexible coil without a significant helical content. However, according to the results given in this paper, a wormlike helical chain seems to be the most adequate model for amylose conformation in neutral solution.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100203
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  • 4
    Electronic Resource
    Electronic Resource
    Optische rotationsdispersion und circulardichroism us der jodkomplexe niedermolekularer amylosen in abhängigkeit vom polymerisationsgrad. 4. Mitteilung3. Mitt., R. C. SCHULZ, R. WOLF und H. MAYERHÖFER, Kolloid-Z. u. Z. Polymere 227 (1968) 65.Frau Professor Dr. E. HUSEMANN mit freundlichen Grüßen zum 60. Geburtstag gewidmet (1969)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 121 (1969), S. 147-158 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: From a series of enzymatically synthesized amyloses with a very narrow molecular weight distribution (Pw/Pn = 1.001-1.002) and degrees of polymerization (Pn) between 25 and 480 the iodine complexes were prepared. The absorption spectra as well as the ORD- and CD-curves of these complexes were recorded. COTTON effects were observed at 365, 485 and in the range of 500-600 mμ. The wavelength of the absorption maximum (λmax) of greatest wavelength and of the positive CD-maximum in the region of 500-600 mμ may be described as functions of Pn by the equation : \documentclass{article}\pagestyle{empty}\begin{document}$$\frac{1}{{\lambda _{\max } }} = \frac{1}{{\rm A}} + \frac{{\rm B}}{{\rm A}} \cdot \frac{1}{{{\rm P}_{\rm n} }} $$\end{document} Furthermore, the extinctions, the base molar rotations and dichroic absorptions have been evaluated as a function of Pn. The base molar rotations and the CD-absorptions exhibited a maximum between Pn 70 to 100 and decreased again at higher Pn. ORD and CD increased on standing of the solutions, whereas the locations of the absorption maxima as well as of the COTTON affects remained unchanged. Possible reasons for this behaviour are discussed.
    Notes: Von einer Reihe enzymatisch synthetisierter Amylosen mit sehr enger Molekulargewichtsverteilung (Pw/Pn = 1,00 bis 1,002) und Polymerisationsgraden (Pn) zwischen 25 und 480 wurden die Jodkomplexe hergestellt. Die Absorptionsspektren sowie die ORD-und CD-Kurven dieser Jodkomplexe wurden aufgenommen. Es treten COTTON-Effeket auf bei 365, 485 und im Bereich von 500-600 mμ. Die Wellenlänge des langwelligen Absorptionsmaximums (λmax) sowie des positiven CD-Maximums als Funktion von Pn lassen sich durch folgende Gleichung beschreiben: \documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{1}{{\lambda _{\max } }} = \frac{1}{{\rm A}} + \frac{{\rm B}}{{\rm A}} \cdot \frac{1}{{{\rm P}_{\rm n} }} $$\end{document} Ferner wurden die Extinktionen, die grundmolaren Drehwerte und die CD-Absorptionen als Funktion von Pn untersucht. Drehwerte und CD-Absorption durchlaufen zwischen Pn 70 und 100 maximale Werte und sinken bei höherem pn wieder ab. Sowohl ORD als auch CD nehmen im Laufe der Zeit zu, obwohl die Extinktionen und die Lage der Absorptionsmaxima und der COTTON-Effekte unverändert bleiben. Mögliche Ursachen werden diskutiert.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1969.021210113
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  • 5
    Electronic Resource
    Electronic Resource
    Asymmetric Reduction of PolyvinylacetophenonePart of the dissertation by H. Mayerhöfer, Mainz D 77. (1968)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 7 (1968), S. 216-217 
    Details
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196802161
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