Photoinduced electron transfer in fixed distance chlorophyll-quinone donor-acceptor molecules
A series of fixed distance chlorophyll-quinone donor-acceptor molecules have been prepared. The donor consists of either methyl pyropheophorbide a or methyl pyrochlorophyllide a, while the acceptor is either benzoquinone or naphthoquinone. The acceptors are fused to a triptycene spacer group, which in turn is attached to the donors at their vinyl groups. Picosecond transient absorption measurements have been used to identify electron transfer from the lowest excited singlet state of the donor to the acceptor as the mechanism of fluorescence quenching in these molecules. The charge separation rate constants increase from 2 x 10/sup 10/ s/sup -1/ to 4 x 10/sup 11/ s/sup -1/ as the free energy of charge separation increases, while the radical pair recombination rate constants decrease from 1.2 x 10/sup 11/ s/sup -1/ to 2 x 10/sup 9/ s/sup -1/ as the free energy of recombination increases. The resulting total reorganization energy lambda = 0.9 eV.
- Research Organization:
- Argonne National Lab., IL (USA)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 6429804
- Report Number(s):
- CONF-870497-2; ON: DE87011412
- Resource Relation:
- Conference: NATO workshop on photoinduced charge separation and energy migration in supramolecular species, Capri, Italy, 5 Apr 1987; Other Information: Paper copy only, copy does not permit microfiche production
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHLOROPHYLL
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
ELECTRON TRANSFER
QUINONES
ABSORPTION SPECTRA
BINDING ENERGY
ELECTRONS
EXCITED STATES
FLUORESCENCE
ION PAIRS
MOLECULES
RADICALS
RECOMBINATION
VALENCE
AROMATICS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
ELEMENTARY PARTICLES
ENERGY
ENERGY LEVELS
FERMIONS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
LEPTONS
LUMINESCENCE
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
PROTEINS
SPECTRA
SYNTHESIS
140505* - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)