Fluorescence quenching of aromatic hydrocarbons by nitroxide radicals: a mechanismatic study
The fluorescence quenching of phenanthrene (Phen), 9-cyanophenanthrene (CPhen), 9-cyanoanthracene (CA), perylene (Per), 9,10-dicyanoanthracene (DCA), and 9,10-diphenylanthracene (DPA) using stable nitroxide radicals as quenchers has been studied by steady state and flash photolysis measurements. Bot...
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| Format: | Article |
| Language: | English |
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Wiley
1999-01-01
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| Series: | International Journal of Photoenergy |
| Online Access: | http://dx.doi.org/10.1155/S1110662X99000306 |
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| _version_ | 1850104801442922496 |
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| author | Tarek A. Fayed Gunter Grampp Stephan Landgraf |
| author_facet | Tarek A. Fayed Gunter Grampp Stephan Landgraf |
| author_sort | Tarek A. Fayed |
| collection | DOAJ |
| description | The fluorescence quenching of phenanthrene (Phen), 9-cyanophenanthrene (CPhen), 9-cyanoanthracene
(CA), perylene (Per), 9,10-dicyanoanthracene (DCA), and 9,10-diphenylanthracene (DPA) using
stable nitroxide radicals as quenchers has been studied by steady state and flash photolysis measurements.
Both linearity and deviation from linearity in the Stern-Volmer plots have been observed. The active sphere
model was used to discuss the upward curvature of the Stern-Volmer plots in case of Per, DCA, and DPA.
The bimolecular quenching rate constant (kq) of Phen, CPhen and CA was found to be diffusion controlled
while in other cases it is lower than the diffusion limit. On the basis of flash photolysis measurements as
well as the overlap between the emission spectra of hydrocarbons and the absorption spectra of radicals,
a resonance energy transfer mechanism is taken place in case of Per, DPA, DCA, and CA. For Phen and
CPhen where the energy gap between the first excited singlet and the nearest lower triplet state is small,
an induced intersystem crossing was suggested. Finally, the quenching process was discussed in terms of
the free energy dependence (ΔG) of the electron transfer from nitroxide radicals to the excited hydrocarbons. |
| format | Article |
| id | doaj-art-4292f4253b0f4bf9b703e0d0928d7e21 |
| institution | DOAJ |
| issn | 1110-662X |
| language | English |
| publishDate | 1999-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | International Journal of Photoenergy |
| spelling | doaj-art-4292f4253b0f4bf9b703e0d0928d7e212025-08-20T02:39:15ZengWileyInternational Journal of Photoenergy1110-662X1999-01-011317317610.1155/S1110662X99000306Fluorescence quenching of aromatic hydrocarbons by nitroxide radicals: a mechanismatic studyTarek A. Fayed0Gunter Grampp1Stephan Landgraf2Institute of Physical and Theoretical Chemistry, Technical University Graz, Technikerstr 4/I, Graz 8010, AustriaInstitute of Physical and Theoretical Chemistry, Technical University Graz, Technikerstr 4/I, Graz 8010, AustriaInstitute of Physical and Theoretical Chemistry, Technical University Graz, Technikerstr 4/I, Graz 8010, AustriaThe fluorescence quenching of phenanthrene (Phen), 9-cyanophenanthrene (CPhen), 9-cyanoanthracene (CA), perylene (Per), 9,10-dicyanoanthracene (DCA), and 9,10-diphenylanthracene (DPA) using stable nitroxide radicals as quenchers has been studied by steady state and flash photolysis measurements. Both linearity and deviation from linearity in the Stern-Volmer plots have been observed. The active sphere model was used to discuss the upward curvature of the Stern-Volmer plots in case of Per, DCA, and DPA. The bimolecular quenching rate constant (kq) of Phen, CPhen and CA was found to be diffusion controlled while in other cases it is lower than the diffusion limit. On the basis of flash photolysis measurements as well as the overlap between the emission spectra of hydrocarbons and the absorption spectra of radicals, a resonance energy transfer mechanism is taken place in case of Per, DPA, DCA, and CA. For Phen and CPhen where the energy gap between the first excited singlet and the nearest lower triplet state is small, an induced intersystem crossing was suggested. Finally, the quenching process was discussed in terms of the free energy dependence (ΔG) of the electron transfer from nitroxide radicals to the excited hydrocarbons.http://dx.doi.org/10.1155/S1110662X99000306 |
| spellingShingle | Tarek A. Fayed Gunter Grampp Stephan Landgraf Fluorescence quenching of aromatic hydrocarbons by nitroxide radicals: a mechanismatic study International Journal of Photoenergy |
| title | Fluorescence quenching of aromatic hydrocarbons by nitroxide radicals: a mechanismatic study |
| title_full | Fluorescence quenching of aromatic hydrocarbons by nitroxide radicals: a mechanismatic study |
| title_fullStr | Fluorescence quenching of aromatic hydrocarbons by nitroxide radicals: a mechanismatic study |
| title_full_unstemmed | Fluorescence quenching of aromatic hydrocarbons by nitroxide radicals: a mechanismatic study |
| title_short | Fluorescence quenching of aromatic hydrocarbons by nitroxide radicals: a mechanismatic study |
| title_sort | fluorescence quenching of aromatic hydrocarbons by nitroxide radicals a mechanismatic study |
| url | http://dx.doi.org/10.1155/S1110662X99000306 |
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