Photophysics and photochemistry of ring-fluorinated stilbenes
| Autor: | W. Luettke, K. Rauch, Ernst Fischer, A. Jakob, Nelly Castel, K.A. Muszkat |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
010405 organic chemistry
Chemistry General Chemical Engineering General Physics and Astronomy chemistry.chemical_element Quantum yield General Chemistry 010402 general chemistry Photochemistry 01 natural sciences Fluorescence Cis trans isomerization 0104 chemical sciences 3. Good health Yield (chemistry) Fluorine Flash photolysis Fluorocarbon Absorption (chemistry) |
| Zdroj: | Journal of Photochemistry and Photobiology A: Chemistry. 56:219-226 |
| ISSN: | 1010-6030 |
| DOI: | 10.1016/1010-6030(91)80022-a |
| Popis: | The absorption and emission spectra, E – Z photo-interconversion, photocyclization of the Z isomers, and transient triplet-triplet (T-T) absorption of five fluoro stilbenes were studied over a wide temperature range, down to 90 K, and compared with stilbene. All five compounds form stable Z (cis) isomers on irradiation, but photocyclization takes place only in the absence of fluorine substitution at the 2,6,2′,6′ positions or the 2,6 positions. For the stilbenes fluorinated in these positions, the quantum yields of E → Z photoconversion and of E fluorescence vary much less on cooling than in stilbene. The fluorescence yield of all the Z isomers is very small even at −180 °C. T-T transients are detected at −170 °C as with trans -stilbene. Their lifetimes are lower than those of stilbene. |
| Databáze: | OpenAIRE |
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