Effect of donor-acceptor orientation on ultrafast photoinduced electron transfer and dark charge recombination in porphyrin-quinone molecules
- Osaka Univ., Ibaraki (Japan)
- Argonne National Lab., IL (United States)
A series of four zinc porphyrin-spacer-benzoquinone molecules were studied in which the spacer is either spiro[4,4]nonane or trans-decalin. The benzoquinone is attached to the porphyrin at two fixed distances each possessing two fixed orientations of the porphyrin relative to the quinone. The rate constants for photoinduced electron transfer from the lowest excited singlet state of the porphyrin to the quinone to form the Zn porphyrin[sup +]-quinone[sup [minus]] ion pair and the subsequent dark charge recombination reaction were measured as a function of solvent polarity. The observed orientation dependent differences in rate constants for these two reactions can be attributed to orientation dependent changes in electronic coupling alone, because the Franck-Condon factors for electron transfer are similar for each molecule. The rate constant data suggest that the donor-acceptor orientation effects observed are due to variations in the sum of the direct, through-space interaction between the donor and acceptor and the indirect, through-solvent term. 44 refs., 4 figs., 4 tabs.
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 7126084
- Journal Information:
- Journal of the American Chemical Society; (United States), Vol. 116:15; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
PHOTOCHEMICAL REACTIONS
CHEMICAL REACTION KINETICS
ZINC COMPLEXES
ELECTRON TRANSFER
COMPILED DATA
FRANCK-CONDON PRINCIPLE
TETRAHYDROFURAN
TOLUENE
ALKYLATED AROMATICS
AROMATICS
CHEMICAL REACTIONS
COMPLEXES
DATA
FURANS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
INFORMATION
KINETICS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
REACTION KINETICS
400201* - Chemical & Physicochemical Properties
400500 - Photochemistry