Resonance Raman spectra of electrochemically generated chlorophyll a cation radical
Soret excitation resonance Raman (RR) spectra of electrochemically generated chlorophyll a cation radical (Chl a/sup /center dot/+/) have been obtained in two solvent systems, dry CH/sub 2/Cl/sub 2/ and CH/sub 2/Cl/sub 2/ with added CH/sub 3/OH. The major RR changes observed upon CHl a oxidation are a five-wavenumber downshift of the 1611- and 1491-cm/sup /minus/1/ core-size-sensitive, intensity and frequency changes in the C/sub a/N stretching region (1300-1400 cm/sup /minus/1/), a loss of intensity for ..nu..(C/sub 9//double bond/O) at 1687 cm/sup /minus/1/, and the presence of a new band at 1717 cm/sup /minus/1/. The significant change in the carbonyl stretching region indicates that there is a large change in electron density at ring V and its peripheral substituents with oxidation and further suggests that Chl a/sup /center dot/+/ favors the end form of the C/sub 9/ keto group.
- Research Organization:
- Univ. of Nebraska, Lincoln (USA)
- DOE Contract Number:
- FG02-84ER13261
- OSTI ID:
- 5992984
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 92:17; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400400* -- Electrochemistry
CARBOXYLIC ACIDS
CATIONS
CHARGED PARTICLES
CHEMISTRY
CHLOROPHYLL
DATA
ELECTROCHEMISTRY
ELECTRON DENSITY
ELECTRONIC STRUCTURE
EXPERIMENTAL DATA
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INELASTIC SCATTERING
INFORMATION
IONS
LASER SPECTROSCOPY
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
PROTEINS
RADICALS
RAMAN SPECTRA
RAMAN SPECTROSCOPY
RESONANCE SCATTERING
SCATTERING
SPECTRA
SPECTROSCOPY