Environmental effects on electron transfer from chlorophyll triplet to quinone: role of dielectric constant, viscosity and quinone structure in cellulose acetate films
The effects of environmental parameters on chlorophyll triplet quenching and electron transfer to quinones have been investigated in a system consisting of donor and acceptor incorporated into a cellulose acetate film which was subsequently exposed to solvent. Triplet quenching by a diffusional mechanism was found to occur in the dry film, with steric effects being a major determinant of quencher effectiveness. No formation of separated radicals was found under these conditions, probably because the high viscosity prevented separation of the initially formed radical-ion pair. When the film was subsequently exposed to water, triplet quenching became more effective and separated radical production occurred. This is attributed to effects of decreased microviscosity and increased dielectric constant. Both steric effects and quinone redox potential were found to influence radical yields. Rate constants for reverse electron transfer were independent of quinone redox potential. When solvents other than pure water were used, radical yields were observed to increase with the dielectric constant. This is ascribed to an increase in the ease of separation of the radical-ion pair.
- Research Organization:
- Arizona Univ., Tucson (USA)
- OSTI ID:
- 6578474
- Report Number(s):
- DOE/ER/04927-T4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
14 SOLAR ENERGY
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500 -- Photochemistry
AROMATICS
BINDING ENERGY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELLULOSE ESTERS
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CHLOROPHYLL
CHLOROPLASTS
DIELECTRIC PROPERTIES
ELECTRICAL PROPERTIES
ELECTRON TRANSFER
ELECTRONS
ELEMENTARY PARTICLES
ENERGY
ESTERS
FERMIONS
FILMS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
KINETICS
LEPTONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHYSICAL PROPERTIES
PHYTOCHROMES
PIGMENTS
PORPHYRINS
QUENCHING
QUINONES
RADICALS
REACTION KINETICS
SYNTHESIS
VALENCE
VISCOSITY
YIELDS
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500 -- Photochemistry
AROMATICS
BINDING ENERGY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELLULOSE ESTERS
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CHLOROPHYLL
CHLOROPLASTS
DIELECTRIC PROPERTIES
ELECTRICAL PROPERTIES
ELECTRON TRANSFER
ELECTRONS
ELEMENTARY PARTICLES
ENERGY
ESTERS
FERMIONS
FILMS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
KINETICS
LEPTONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHYSICAL PROPERTIES
PHYTOCHROMES
PIGMENTS
PORPHYRINS
QUENCHING
QUINONES
RADICALS
REACTION KINETICS
SYNTHESIS
VALENCE
VISCOSITY
YIELDS