Light-Induced Tyrosine Radical Formation from Ruthenium-Tyrosine Complex Anchored to SnO2 Semiconductor

Steady state spectroscopy and flash photolysis measurements were used to study the multistep electron transfer in a supramolecular complex adsorbed on the surface of nanocrystalline SnO2 in order to mimic the function of the tyrosineZ and chlorophyll unit P680 in natural photosystem II (PSII). A rut...

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Main Author: Raed Ghanem
Format: Article
Language:English
Published: Wiley 2008-01-01
Series:International Journal of Photoenergy
Online Access:http://dx.doi.org/10.1155/2008/524142
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author Raed Ghanem
author_facet Raed Ghanem
author_sort Raed Ghanem
collection DOAJ
description Steady state spectroscopy and flash photolysis measurements were used to study the multistep electron transfer in a supramolecular complex adsorbed on the surface of nanocrystalline SnO2 in order to mimic the function of the tyrosineZ and chlorophyll unit P680 in natural photosystem II (PSII). A ruthenium(II)-tris(bipyridyl) complex covalently linked to an L-tyrosine ethyl ester through an amide bond was anchored to the surface of nanocrystalline SnO2 via four carboxylic acid groups linked to the bpy ligands. The apparent association constant for the association between ruthenium(II)-tris(bipyridyl) complex and SnO2 is 3.2×106M−1 and a degree of association up to 99% was determined. 450 nm excitation of the complex promotes an electron to a metal-to-ligand charge transfer (MLCT) excited state, from which the electron is injected into SnO2. The photogeneration of Ru(III) is followed by an intramolecular electron transfer from tyrosine to Ru(III), regenerating the photosensitizer Ru(II) and forming the tyrosyl radical. The tyrosyl radical is formed in less than 3 microseconds with a yield of 32%.
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spelling doaj-art-d59eb148fe1149c4a9e0bc77c0976e6e2025-02-03T01:07:19ZengWileyInternational Journal of Photoenergy1110-662X1687-529X2008-01-01200810.1155/2008/524142524142Light-Induced Tyrosine Radical Formation from Ruthenium-Tyrosine Complex Anchored to SnO2 SemiconductorRaed Ghanem0Department of Chemistry, University of Al al-Bayt, P.O. Box 130040, Mafraq 25113, JordanSteady state spectroscopy and flash photolysis measurements were used to study the multistep electron transfer in a supramolecular complex adsorbed on the surface of nanocrystalline SnO2 in order to mimic the function of the tyrosineZ and chlorophyll unit P680 in natural photosystem II (PSII). A ruthenium(II)-tris(bipyridyl) complex covalently linked to an L-tyrosine ethyl ester through an amide bond was anchored to the surface of nanocrystalline SnO2 via four carboxylic acid groups linked to the bpy ligands. The apparent association constant for the association between ruthenium(II)-tris(bipyridyl) complex and SnO2 is 3.2×106M−1 and a degree of association up to 99% was determined. 450 nm excitation of the complex promotes an electron to a metal-to-ligand charge transfer (MLCT) excited state, from which the electron is injected into SnO2. The photogeneration of Ru(III) is followed by an intramolecular electron transfer from tyrosine to Ru(III), regenerating the photosensitizer Ru(II) and forming the tyrosyl radical. The tyrosyl radical is formed in less than 3 microseconds with a yield of 32%.http://dx.doi.org/10.1155/2008/524142
spellingShingle Raed Ghanem
Light-Induced Tyrosine Radical Formation from Ruthenium-Tyrosine Complex Anchored to SnO2 Semiconductor
International Journal of Photoenergy
title Light-Induced Tyrosine Radical Formation from Ruthenium-Tyrosine Complex Anchored to SnO2 Semiconductor
title_full Light-Induced Tyrosine Radical Formation from Ruthenium-Tyrosine Complex Anchored to SnO2 Semiconductor
title_fullStr Light-Induced Tyrosine Radical Formation from Ruthenium-Tyrosine Complex Anchored to SnO2 Semiconductor
title_full_unstemmed Light-Induced Tyrosine Radical Formation from Ruthenium-Tyrosine Complex Anchored to SnO2 Semiconductor
title_short Light-Induced Tyrosine Radical Formation from Ruthenium-Tyrosine Complex Anchored to SnO2 Semiconductor
title_sort light induced tyrosine radical formation from ruthenium tyrosine complex anchored to sno2 semiconductor
url http://dx.doi.org/10.1155/2008/524142
work_keys_str_mv AT raedghanem lightinducedtyrosineradicalformationfromrutheniumtyrosinecomplexanchoredtosno2semiconductor