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
