Tryptophan Quenching of Zinc-Phthalocyanine and Porphycene Fluorescence in Micellar CTAC

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Singlet excited state deactivation of a zinc phthalocyanine (ZnPc), porphycene (Po) and tetrapropyl-porphycene (PrPo) by anionic tryptophan (Trp-) were investigated in cetyltrimethylammonium chloride (CTAC) micelles at pH 9.2 ± 0.1, regulated by a Tris buffer. Data obtained from steady-state experim...

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Autores principales: Daraio, M.E., Völker, A., Aramendía, P.F., San Román, E.
Formato: JOUR
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00318655_v67_n4_p371_Daraio
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_00318655_v67_n4_p371_Daraio2023-10-03T14:41:32Z Tryptophan Quenching of Zinc-Phthalocyanine and Porphycene Fluorescence in Micellar CTAC Daraio, M.E. Völker, A. Aramendía, P.F. San Román, E. Singlet excited state deactivation of a zinc phthalocyanine (ZnPc), porphycene (Po) and tetrapropyl-porphycene (PrPo) by anionic tryptophan (Trp-) were investigated in cetyltrimethylammonium chloride (CTAC) micelles at pH 9.2 ± 0.1, regulated by a Tris buffer. Data obtained from steady-state experiments over a wide range of detergent and added NaCl concentrations were analyzed by using a pseudophase ion-exchange model (Abuin et al., J. Phys. Chem. 87, 5166-5172, 1983). The model was applied to derive singlet quenching rate constants for ZnPc and the porphycenes by Trp and the selectivity coefficient for Trp-/Cl- exchange at the micellar surface. The results point to an electron transfer quenching. Neutral tryptophan also quenches efficiently ZnPc fluorescence in CTAC without added buffer and Trp- does not deactivate the triplet state of these dyes. By flash photolysis, only the absorption of the triplet species was detected. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00318655_v67_n4_p371_Daraio
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description Singlet excited state deactivation of a zinc phthalocyanine (ZnPc), porphycene (Po) and tetrapropyl-porphycene (PrPo) by anionic tryptophan (Trp-) were investigated in cetyltrimethylammonium chloride (CTAC) micelles at pH 9.2 ± 0.1, regulated by a Tris buffer. Data obtained from steady-state experiments over a wide range of detergent and added NaCl concentrations were analyzed by using a pseudophase ion-exchange model (Abuin et al., J. Phys. Chem. 87, 5166-5172, 1983). The model was applied to derive singlet quenching rate constants for ZnPc and the porphycenes by Trp and the selectivity coefficient for Trp-/Cl- exchange at the micellar surface. The results point to an electron transfer quenching. Neutral tryptophan also quenches efficiently ZnPc fluorescence in CTAC without added buffer and Trp- does not deactivate the triplet state of these dyes. By flash photolysis, only the absorption of the triplet species was detected.
format JOUR
author Daraio, M.E.
Völker, A.
Aramendía, P.F.
San Román, E.
spellingShingle Daraio, M.E.
Völker, A.
Aramendía, P.F.
San Román, E.
Tryptophan Quenching of Zinc-Phthalocyanine and Porphycene Fluorescence in Micellar CTAC
author_facet Daraio, M.E.
Völker, A.
Aramendía, P.F.
San Román, E.
author_sort Daraio, M.E.
title Tryptophan Quenching of Zinc-Phthalocyanine and Porphycene Fluorescence in Micellar CTAC
title_short Tryptophan Quenching of Zinc-Phthalocyanine and Porphycene Fluorescence in Micellar CTAC
title_full Tryptophan Quenching of Zinc-Phthalocyanine and Porphycene Fluorescence in Micellar CTAC
title_fullStr Tryptophan Quenching of Zinc-Phthalocyanine and Porphycene Fluorescence in Micellar CTAC
title_full_unstemmed Tryptophan Quenching of Zinc-Phthalocyanine and Porphycene Fluorescence in Micellar CTAC
title_sort tryptophan quenching of zinc-phthalocyanine and porphycene fluorescence in micellar ctac
url http://hdl.handle.net/20.500.12110/paper_00318655_v67_n4_p371_Daraio
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AT volkera tryptophanquenchingofzincphthalocyanineandporphycenefluorescenceinmicellarctac
AT aramendiapf tryptophanquenchingofzincphthalocyanineandporphycenefluorescenceinmicellarctac
AT sanromane tryptophanquenchingofzincphthalocyanineandporphycenefluorescenceinmicellarctac
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