| Item type: | Article | ||||
|---|---|---|---|---|---|
| Journal or Publication Title: | Chemical Physics | ||||
| Publisher: | ELSEVIER SCIENCE BV | ||||
| Place of Publication: | AMSTERDAM | ||||
| Volume: | 337 | ||||
| Number of Issue or Book Chapter: | 1-3 | ||||
| Page Range: | pp. 99-109 | ||||
| Date: | 2007 | ||||
| Institutions: | Physics > Institute of Experimental and Applied Physics > Alumni or Retired Professors > Group Alfons Penzkofer Chemistry and Pharmacy > Institut für Organische Chemie > Alumni or Retired Professors > Prof. Dr. Jörg Daub | ||||
| Identification Number: |
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| Keywords: | EMISSION SPECTROSCOPIC CHARACTERIZATION; BLUE-LIGHT PHOTORECEPTORS; PHENOTHIAZINE-PYRENE DYADS; INTRAMOLECULAR ELECTRON-TRANSFER; CHLAMYDOMONAS-REINHARDTII; RHODOBACTER-SPHAEROIDES; ARTIFICIAL PHOTOSYNTHESIS; SUPRAMOLECULAR SYSTEMS; SENSORY PHOTORECEPTORS; STRUCTURAL-CHANGES; isoalloxazine; flavin; phenothiazine; pyrene; triad; absorption spectroscopy; fluorescence spectroscopy; photo-degradation; forster-type energy transfer; reductive electron-transfer; oxidative electron transfer; charge recombination; blue-light photoreceptor model; cryptochrome model | ||||
| Dewey Decimal Classification: | 500 Science > 530 Physics 500 Science > 540 Chemistry & allied sciences | ||||
| Status: | Published | ||||
| Refereed: | Yes, this version has been refereed | ||||
| Created at the University of Regensburg: | Yes | ||||
| Item ID: | 68924 |
Abstract
(alpha R)-alpha-[[[10-[4-(10-heptyl-10H-phenothiazin-3-yl)phenyl]-4,10-dihydro-2,4-dioxobenzo[g]pteridin-3(2H)-yl]acetyl]amino]pyrenepropionic acid phenylmethyl ester, a pyrene-isoalloxazine(flavin)-phenothiazine triad (abbreviated as PYFPT), was designed to mimic the dye-based functions of cryptochromes. PYFPT dissolved in dichloromethane and acetonitrile is characterized by absorption and ...
Abstract
(alpha R)-alpha-[[[10-[4-(10-heptyl-10H-phenothiazin-3-yl)phenyl]-4,10-dihydro-2,4-dioxobenzo[g]pteridin-3(2H)-yl]acetyl]amino]pyrenepropionic acid phenylmethyl ester, a pyrene-isoalloxazine(flavin)-phenothiazine triad (abbreviated as PYFPT), was designed to mimic the dye-based functions of cryptochromes. PYFPT dissolved in dichloromethane and acetonitrile is characterized by absorption and fluorescence spectroscopy. Absorption cross-section spectra, fluorescence quantum distributions and quantum yields, degrees of fluorescence polarisation, and fluorescence lifetimes are determined. The triad is highly photo-stable as has been shown by monitoring absorption spectra under prolonged blue-light exposure. The absorption spectrum of PYFPT resembles the superposition of the absorption of the isoalloxazine (flavin), pyrene, and phenothiazine subchromophores. Blue light (lambda(exc) = 428 nm) excites exclusively the isoalloxazine subunit causing reductive electron transfer from the phenothiazine subchromophore to the locally excited isoalloxazine with a time constant of approximately 600 fs under formation of a charge transfer state which subsequently undergoes charge recombination. Near ultraviolet radiation (lambda(exc) = 311 nm) causes simultaneous excitation of the isoalloxazine, pyrene, and phenothiazine chromophores. Both, the locally excited pyrene and phenothiazine moieties cause oxidative electron transfer to the flavin moiety with time constants of about 80 ps and 50 ps followed by subsequent charge recombination. Forster-type energy transfer processes have been found to be one to two orders of magnitude slower. (c) 2007 Elsevier B.V. All rights reserved.
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