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  • 1
    Electronic Resource
    Electronic Resource
    Isolation by high-pressure liquid chromatography, configurational determination by 1H-NMR, and analyses of electronic absorption and raman spectra of isomeric spheroidene (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Biospectroscopy 2 (1996), S. 47-58 
    Details
    ISSN: 1075-4261
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A set of cis-trans isomers of spheroidene (all-trans, 9′-cis, 13′-cis, 9-cis, 13-cis, 5,9′-cis, 9,13′-cis, and 5,13-cis + 13,9′-cis) were isolated from an isomeric mixture which was obtained by iodine-sensitized photoisomerization of the all-trans isomer by means of high-pressure liquid chromatography (HPLC) using a calcium hydroxide column. The 15-cis isomer was isolated from the reaction center (RC) of Rhodobacter sphaeroides 2.4.1. The configurations of the above isomers were determined by 1H-nuclear magnetic resonance (NMR) spectroscopy. The order of elution of the isomers in HPLC is explained in terms of the interaction between the extended all-trans part of the various cis-trans configurations of the conjugated backbone and the flat surface of calcium hydroxide at the molecular level. A systematic change from a peripheral-cis toward a central-cis isomer was found, for mono-cis isomers except for 15-cis, in the wavelength of the 1Ag- → 1Bu+ absorption and in the relative intensity of the C10(single bond)C11 (C10′(single bond)C11′) vs. C14(single bond)C15 (C14′(single bond)C15′) stretching Raman lines. © 1996 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    The structures of S0 spheroidene in the light-harvesting (LH2) complex and S0 and T1 spheroidene in the reaction center of Rhodobacter sphaeroides 2.4.1 as revealed by Raman spectroscopy (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Biospectroscopy 2 (1996), S. 59-69 
    Details
    ISSN: 1075-4261
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The Raman spectrum of S0 spheroidene in the light-harvesting (LH2) complex (LHC) and those of S0 and T1 spheroidene in the reaction center (RC) of Rhodobacter sphaeroides 2.4.1 were recorded. Comparison of the S0 Raman spectrum of the all-trans isomer bound to the LHC of R. sphaeroides 2.4.1 with that free in n-hexane solution suggests that the LHC-bound carotenoid takes a flat, all-trans configuration with possible distortion in the plane of the conjugated chain. On the other hand comparison of the S0 Raman spectrum of the 15-cis isomer bound to the RC with that free in n-hexane solution suggests that the RC-bound carotenoid takes a 15-cis configuration which is twisted around the C15(double bond)C15′ bond and distorted in the (single bond)C15H(double bond)C15′H(single bond) plane. The T1 Raman spectra of the RC-bound spheroidene indicated substantial twisting and in-plane distortion of the conjugated backbone. Based on the above results, a mechanism of triplet-energy dissipation by the RC-bound carotenoid, which involves an internal rotation around the C15(double bond)C15′ bond, is proposed. © 1996 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
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