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Title: Solvent effects on the resonance Raman and electronic absorption spectra of bacteriochlorophyll a cation radical

Abstract

Resonance Raman and electronic absorption spectra of bacteriocholrophyll a cation radical (BChl a{sup .+}) were recorded in 14 different kinds of solvents. The frequency of the ring-breathing Raman band of BChl a{sup .+} was in the region of 1596-1599 cm{sup -1} in solvents forming the pentacoordinated state in neutral bacteriochlorophyll a (BChl a), while it was in the region of 1584-1588 cm{sup -1} in solvents forming the hexacoordinated state. BChl a{sup .+} exhibited a key absorption band in the regions 546-554 and 557-563 nm in the above penta- and hexa-coordinating solvents. Therefore, it has been concluded that the penta- and hexa-coordinated states are retained even after conversion of BChl a into BChl a{sup .+} (one-electron oxidization). Application of this rule to the case of 2-propanol solution showed transformation from the penta- to the hexa-coordinated state upon one-electron oxidation in this particular solution. The coordination states of BChl a{sup .+} could be correlated with the donor number(DN) and the Taft parameters, {Beta} and {pi}{sup *}, of the solvent: The hexacoordinated state was formed in solvents with DN >= 18 or {Beta} > 0.5 showing higher electron donating power, while the pentacoordinated state was formed in solvents with {pi}{sup *} > 0.65more » showing higher dielectric stabilization. 27 refs., 8 figs., 3 tabs.« less

Authors:
;  [1]; ;  [2]
  1. Waseda Univ., Tokyo (Japan)
  2. Kwansei Gakuin Univ., Nishinomiya (Japan)
Publication Date:
OSTI Identifier:
219696
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry; Journal Volume: 100; Journal Issue: 6; Other Information: PBD: 8 Feb 1996
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; 55 BIOLOGY AND MEDICINE, BASIC STUDIES; PHOTOSYNTHETIC REACTION CENTERS; ABSORPTION SPECTRA; RAMAN SPECTRA; PROTEINS; RADICALS; SOLVATION; CHLOROPHYLL; PHOTOSYNTHESIS; SOLVENTS; CATIONS; MOLECULAR STRUCTURE

Citation Formats

Misono, Yasuhito, Itoh, Koichi, Limanatara, Leenawaty, and Koyama, Yasushi. Solvent effects on the resonance Raman and electronic absorption spectra of bacteriochlorophyll a cation radical. United States: N. p., 1996. Web. doi:10.1021/jp952295m.
Misono, Yasuhito, Itoh, Koichi, Limanatara, Leenawaty, & Koyama, Yasushi. Solvent effects on the resonance Raman and electronic absorption spectra of bacteriochlorophyll a cation radical. United States. doi:10.1021/jp952295m.
Misono, Yasuhito, Itoh, Koichi, Limanatara, Leenawaty, and Koyama, Yasushi. Thu . "Solvent effects on the resonance Raman and electronic absorption spectra of bacteriochlorophyll a cation radical". United States. doi:10.1021/jp952295m.
@article{osti_219696,
title = {Solvent effects on the resonance Raman and electronic absorption spectra of bacteriochlorophyll a cation radical},
author = {Misono, Yasuhito and Itoh, Koichi and Limanatara, Leenawaty and Koyama, Yasushi},
abstractNote = {Resonance Raman and electronic absorption spectra of bacteriocholrophyll a cation radical (BChl a{sup .+}) were recorded in 14 different kinds of solvents. The frequency of the ring-breathing Raman band of BChl a{sup .+} was in the region of 1596-1599 cm{sup -1} in solvents forming the pentacoordinated state in neutral bacteriochlorophyll a (BChl a), while it was in the region of 1584-1588 cm{sup -1} in solvents forming the hexacoordinated state. BChl a{sup .+} exhibited a key absorption band in the regions 546-554 and 557-563 nm in the above penta- and hexa-coordinating solvents. Therefore, it has been concluded that the penta- and hexa-coordinated states are retained even after conversion of BChl a into BChl a{sup .+} (one-electron oxidization). Application of this rule to the case of 2-propanol solution showed transformation from the penta- to the hexa-coordinated state upon one-electron oxidation in this particular solution. The coordination states of BChl a{sup .+} could be correlated with the donor number(DN) and the Taft parameters, {Beta} and {pi}{sup *}, of the solvent: The hexacoordinated state was formed in solvents with DN >= 18 or {Beta} > 0.5 showing higher electron donating power, while the pentacoordinated state was formed in solvents with {pi}{sup *} > 0.65 showing higher dielectric stabilization. 27 refs., 8 figs., 3 tabs.},
doi = {10.1021/jp952295m},
journal = {Journal of Physical Chemistry},
number = 6,
volume = 100,
place = {United States},
year = {Thu Feb 08 00:00:00 EST 1996},
month = {Thu Feb 08 00:00:00 EST 1996}
}