Excited state structural relaxation relaxation of N-(1-anthryl)-2,4,6-trimethyl-pyridinium cation
The fluorescence spectrum of N-(1-anthryl)-2,4,6-trimethylpyridinium cation (1) has an anomalously high Stokes' shift. The fluorescence spectra of 1 in ethanol and butyronitrile are shifted to shortwavelength region and fluorescence quantum yield increases as the temperature decreases. The fluo...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2004-01-01
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| Series: | International Journal of Photoenergy |
| Online Access: | http://dx.doi.org/10.1155/S1110662X04000108 |
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| Summary: | The fluorescence spectrum of N-(1-anthryl)-2,4,6-trimethylpyridinium cation (1) has an anomalously
high Stokes' shift. The fluorescence spectra of 1 in ethanol and butyronitrile are shifted to shortwavelength
region and fluorescence quantum yield increases as the temperature decreases. The fluorescence
rate constant of this compound changes considerably (6 times in ethanol and 15 times in butyronitrile) as
the temperature decreases from 293 K (relaxed state) to 77 K (mainly nonrelaxed state). It points out that at
these temperatures the fluorescence takes place from two species with different structures. It is concluded
that anomalously high fluorescence Stokes' shift of 1 is caused by both solvent orientation relaxation and
excited state structural relaxation consisting in the mutual rotation of anthracene and pyridinium fragments
of the cation and resulting in the formation of a specie with different structure. The rates of these processes
are determined by the temperature-dependent viscosity of the medium. |
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| ISSN: | 1110-662X |