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  • 1
    Electronic Resource
    Electronic Resource
    Photochromism of 4-acryloxyazobenzene/(-)-menthyl acrylate copolymers (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1267-1280 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Copolymers of trans-4-acryloxyazobenzene (AAB) with (-)-menthyl acrylate (MtA) have been prepared by free radical initiation; comonomer reactivity ratios have been found to be rAAB = 0.89 and rMtA = 0.53. Dependence of chiroptical properties on copolymer composition has been investigated and contribution to circular dichroism by azobenzene chromophores of isolated and sequence AAB units, as well as the influence of the trans to cis photoisomerization, have been determined. Kinetics of photoinduced trans → cis and thermally induced cis → trans isomerization of azobenzene side chains have also been examined and the kinetic parameters evaluated with relation to copolymer structure. The results have been discussed in terms of light-induced secondary structure reversible modifications.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170220607
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  • 2
    Electronic Resource
    Electronic Resource
    Optically active copolymers from p-vinyltrifluoroacetophenone (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1693-1698 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Copolymers of p-vinyltrifluoroacetophenone (VTFA) with optically active (-)-menthyl acrylate (MtA) have been prepared by free radical initiation. The values of reactivity ratios (rVTFA = 4.28 and rMtA = 0.26) indicate that counits are inserted substantially at random into the copolymer macromolecules. CD spectra show a couplet typical of exciton splitting in the absorption region of trifluoromethylphenyl (TFA) chromophore. Dependence of ellipticity on composition and sequence distribution suggests that TFA chromophores are in a chiral environment provided by the dissymmetric conformation of the copolymer macromolecules.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.170210612
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  • 3
    Electronic Resource
    Electronic Resource
    Optically active hydrocarbon polymers with aromatic side chains. II. Poly-(S)-p-sec-butylstyreneFor the previous paper of this series see Chiellini et al.1 (1972)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 10 (1972), S. 809-822 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of optically active p-sec-butylstyrene (I) has been carried out starting with (S)-2-phenylbutane (II) having optical purity 88-91%. The optical purity of I thus obtained was found to be 73-75%. The polymerization of I with stereospecific coordinated anionic catalysts gave amorphous polymers, as in the case of many other p-substituted styrene derivatives. The fractions obtained from these polymers have very similar rotatory power at 589 nm which is practically equal to that of polymer of I obtained by nonstereospecific radical initiator and of low molecular weight structural models. Accordingly the 1Lb electronic transition of the aromatic chromophore shows a very low rotatory strength in all samples examined. This result is related to the lack in solution of conformations with a predominant single chirality of the main chain of the macromolecules derived from I.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1972.150100316
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    Paper (German National Licenses)
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