Negative shift of chlorophyll a oxidation potential by aggregation in acetonitrile/ionic liquid mixed solvents

Spectroscopic and electrochemical properties of chlorophyll (Chl) a aggregates in mixed solvents of acetonitrile and an ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF 4), were examined. The red-shifted absorption peak of the Q y band due to Chl a aggregation as well as the log[Ch...

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Published inJournal of photochemistry and photobiology. A, Chemistry. Vol. 202; no. 2; pp. 191 - 195
Main Authors Kuroiwa, Yoshinori, Kato, Yuki, Watanabe, Tadashi
Format Journal Article
LanguageEnglish
Published Elsevier B.V 25.02.2009
Subjects
Aggregation
Chlorophyll
Dimerization
Photosynthesis
Aggregation
Chlorophyll
SWV
Chl
Photosynthesis
AN
Dimerization
EMIBF 4
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Summary:Spectroscopic and electrochemical properties of chlorophyll (Chl) a aggregates in mixed solvents of acetonitrile and an ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF 4), were examined. The red-shifted absorption peak of the Q y band due to Chl a aggregation as well as the log[Chl a aggregate] against log[Chl a monomer] plot suggested the formation of low-order aggregates such as a dimer. Square wave voltammetry revealed that the first oxidation potential of the Chl a aggregate in the AN/EMIBF 4 mixed solvents is shifted negatively by 130 mV from that of Chl a monomer. In comparison with the redox potential of Chl a in vivo, a tuning mechanism of the redox potentials for photosynthetic species due to dimerization/aggregation is discussed.
ISSN:1010-6030
1873-2666
DOI:10.1016/j.jphotochem.2008.12.006