Non-bonding molecular factors influencing the stretching wavenumbers of the conjugated carbonyl groups of bacteriochlorophyll a

Details

Serval ID
serval:BIB_87DEF8F47251
Type
Article: article from journal or magazin.
Collection
Publications
Title
Non-bonding molecular factors influencing the stretching wavenumbers of the conjugated carbonyl groups of bacteriochlorophyll a
Journal
Journal of Raman Spectroscopy
Author(s)
Lapouge K., Näveke A., Sturgis J.N., Hartwich G., Renaud D., Simonin I., Lutz M., Scheer H., Robert B.
ISSN
0377-0486
Publication state
Published
Issued date
1998
Peer-reviewed
Oui
Volume
29
Number
10-11
Pages
977-981
Language
english
Abstract
The influence of the macrocycle core size on the keto and acetyl carbonyl stretching wavenumbers of bacteriochlorophyll a and of its Co, Ni, Cu and Zn derivatives was examined. Their sensitivity to the polarity and polarizability of the molecular environment was also studied. It is concluded that the macrocycle core size has a clear, but limited, influence on these wavenumbers. As a consequence, interchange between the five- and six-coordinated states of the central Mg atom of bacteriochlorophyll a should shift the keto and acetyl carbonyl stretching wavenumbers, but by not more than 3 and 1 cm(-1), respectively. In line with previous observations on chlorophylls, a marked dependence of the keto and acetyl carbonyl stretching wavenumbers of bacteriophaeophytin a and of bacteriochlorophyll a and its Ni and Zn derivatives on solvent permittivity and refractive index was observed. The sensitivity of the keto carbonyl wavenumber appears to be largely independent of the presence and nature of the central metal and is very close to that reported earlier for chlorophyll a. The wavenumber of the acetyl carbonyl stretching mode of bacteriochlorophyll a derivatives is overall less sensitive to any of these parameters than that of the keto carbonyl group.
Keywords
RESONANCE RAMAN-SPECTROSCOPY, BACTERIAL REACTION-CENTER, PRIMARY ELECTRON-DONOR, RHODOBACTER-SPHAEROIDES, PURPLE BACTERIA, CHLOROPHYLL-A, BINDING-SITE, SPECTRA, ABSORPTION, PROTEINS
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28/11/2011 15:24
Last modification date
20/08/2019 14:47
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