Towards a vibrational analysis of spheroidene. Resonance Raman spectroscopy of 13C-labelled spheroidenes in petroleum ether and in the Rhodobacter sphaeroides reaction centre.
We report resonance Raman spectra of the carotenoid spheroidene and its 14'-13C and 15'-13C substituted analogues in petroleum ether and bound to the reaction centre of Rhodobacter sphaeroides R26. The spectra in petroleum ether correspond to planar all-trans spheroidene while those of the reaction centres are consistent with a nonplanar 15,15'-cis spheroidene. The effect of 13C labelling is largest in the carbon-carbon double-bond stretching region. The 15'-13C substitution of the reaction centre bound spheroidene, however, hardly changes the C=C band as compared to that for the natural abundance spheroidene apart from a new weak band at 1508 cm(-1). This observation has been interpreted as a decoupling of the C15=C15' stretch from the other double-bond stretches in combination with a small intrinsic Raman intensity of this local mode for 15,15'-cis spheroidene.
Kok
P
P
Centre for the Study of Excited States of Molecules, Huygens Laboratory, Leiden University, The Netherlands.
Köhler
J
J
Groenen
E J
EJ
Gebhard
R
R
van der Hoef
I
I
Lugtenburg
J
J
Hoff
A F
AF
Farhoosh
R
R
Frank
H A
HA
D000473:Alkanes; D002250:Carbon Radioisotopes; D002338:Carotenoids / Q000737:chemistry*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D012242:Rhodobacter sphaeroides / Q000737:chemistry*; D013059:Spectrum Analysis, Raman
D000473:Alkanes; D002250:Carbon Radioisotopes; D045322:Photosynthetic Reaction Center Complex Proteins; C005637:spheroidene; D002338:Carotenoids; C004544:naphtha