Chlorophyll photochemistry in condensed media: triplet state quenching and electron transfer to quinone in cellulose acetate films
Chlorophyll a was incorporated into cellulose acetate films and the triplet decay and electron transfer to p-benzoquinone in aqueous solution was studied using laser flash photolysis and ESR. The triplet was found to decay by first order kinetics with the same rate constant regardless of chlorophyll concentration, but the yield was concentration dependent. This is due to quenching at the ground and/or singlet state levels. In the presence of quinone, the triplet is quenched and, when the quinone is in an aqueous solution in contact with the film, chlorophyll cation radical (C./sup +/) as well as the semiquinone anion radical (Q./sup -/) can be observed. The C./sup +/ decays by second order kinetics with a rate constant of 1.5 x 10/sup 6/ M/sup -1/ sec/sup -1/. Although triplet conversion to radicals is slightly lower in the films as compared to homogeneous solutions (approx. 3 times), the lifetimes of the radicals are greatly increased (approx. 10/sup 3/ times).
- Research Organization:
- Arizona Univ., Tucson (USA)
- DOE Contract Number:
- ER-78-S-02-4927
- OSTI ID:
- 5938590
- Report Number(s):
- DOE/ER/04927-1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
550200 -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ACETIC ACID ESTERS
AQUEOUS SOLUTIONS
AROMATICS
BENZOQUINONES
BIOCHEMICAL REACTION KINETICS
CARBOXYLIC ACID ESTERS
CARBOXYLIC ACIDS
CELLULOSE ESTERS
CHEMICAL REACTIONS
CHEMISTRY
CHLOROPHYLL
DATA
DATA FORMS
DECOMPOSITION
DISPERSIONS
ELECTROMAGNETIC RADIATION
ELECTRON SPIN RESONANCE
ELECTRON TRANSFER
ESTERS
EXPERIMENTAL DATA
FILMS
GRAPHS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
IN VITRO
INFORMATION
ISOLATED VALUES
KINETICS
LASER RADIATION
MAGNETIC RESONANCE
MIXTURES
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOCHEMISTRY
PHOTOLYSIS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
QUINONES
RADIATIONS
RADICALS
REACTION KINETICS
RESONANCE
SOLUTIONS
400500* -- Photochemistry
550200 -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ACETIC ACID ESTERS
AQUEOUS SOLUTIONS
AROMATICS
BENZOQUINONES
BIOCHEMICAL REACTION KINETICS
CARBOXYLIC ACID ESTERS
CARBOXYLIC ACIDS
CELLULOSE ESTERS
CHEMICAL REACTIONS
CHEMISTRY
CHLOROPHYLL
DATA
DATA FORMS
DECOMPOSITION
DISPERSIONS
ELECTROMAGNETIC RADIATION
ELECTRON SPIN RESONANCE
ELECTRON TRANSFER
ESTERS
EXPERIMENTAL DATA
FILMS
GRAPHS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
IN VITRO
INFORMATION
ISOLATED VALUES
KINETICS
LASER RADIATION
MAGNETIC RESONANCE
MIXTURES
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOCHEMISTRY
PHOTOLYSIS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
QUINONES
RADIATIONS
RADICALS
REACTION KINETICS
RESONANCE
SOLUTIONS