Mechanism of deactivation processes of excited iron(III) thiocyanato complexes with benacen-type ligands

The complexes [Fe(4-R-benacen)(CH3OH)(NCS)], where 4-R-benacen2− are tetradentate open-chain N,N′-ethylenebis(4-R-benzoylacetoneiminato) N2O2-ligands (R=H, Cl, Br, OCH3), are redox stable in the dark in methanolic solutions. Irradiation of the complexes into intraligand and/or ligand-to-metal charge...

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Main Authors: Jozef Šima, Mário Izakovič, Marián Žitňanský
Format: Article
Language:English
Published: Wiley 2006-01-01
Series:International Journal of Photoenergy
Online Access:http://dx.doi.org/10.1155/IJP/2006/78234
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author Jozef Šima
Mário Izakovič
Marián Žitňanský
author_facet Jozef Šima
Mário Izakovič
Marián Žitňanský
author_sort Jozef Šima
collection DOAJ
description The complexes [Fe(4-R-benacen)(CH3OH)(NCS)], where 4-R-benacen2− are tetradentate open-chain N,N′-ethylenebis(4-R-benzoylacetoneiminato) N2O2-ligands (R=H, Cl, Br, OCH3), are redox stable in the dark in methanolic solutions. Irradiation of the complexes into intraligand and/or ligand-to-metal charge-transfer bands induces a series of photophysical and photochemical deactivation processes leading to Fe(II) and CH2O as final products in a 2:1 molar ratio. Formation of polystyrene containing bonded NCS group when irradiating the complexes in the presence of styrene monomer used as a radical scavenger indicates that the primary photoreduction of Fe(III) to Fe(II) is accompanied by the oxidation of NCS− ligand to •NCS radical. 4-R-benacen-ligands behave as an innocent moiety virtually not participating in the photoinduced redox processes. The quantum yield of Fe(II) formation ΦFe(II) decreases significantly with increased wavelength of the incident radiation, and is slightly influenced by the peripheral groups R of the 4-R-benacen-ligands.
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spelling doaj-art-e1e8197994bf43eda3c5ab2c038df7f62025-08-20T03:20:58ZengWileyInternational Journal of Photoenergy1110-662X1687-529X2006-01-01200610.1155/IJP/2006/7823478234Mechanism of deactivation processes of excited iron(III) thiocyanato complexes with benacen-type ligandsJozef Šima0Mário Izakovič1Marián Žitňanský2Department of Inorganic Chemistry, Slovak Technical University, Radlinského 9, Bratislava 81237, SlovakiaDepartment of Inorganic Chemistry, Slovak Technical University, Radlinského 9, Bratislava 81237, SlovakiaDepartment of Inorganic Chemistry, Slovak Technical University, Radlinského 9, Bratislava 81237, SlovakiaThe complexes [Fe(4-R-benacen)(CH3OH)(NCS)], where 4-R-benacen2− are tetradentate open-chain N,N′-ethylenebis(4-R-benzoylacetoneiminato) N2O2-ligands (R=H, Cl, Br, OCH3), are redox stable in the dark in methanolic solutions. Irradiation of the complexes into intraligand and/or ligand-to-metal charge-transfer bands induces a series of photophysical and photochemical deactivation processes leading to Fe(II) and CH2O as final products in a 2:1 molar ratio. Formation of polystyrene containing bonded NCS group when irradiating the complexes in the presence of styrene monomer used as a radical scavenger indicates that the primary photoreduction of Fe(III) to Fe(II) is accompanied by the oxidation of NCS− ligand to •NCS radical. 4-R-benacen-ligands behave as an innocent moiety virtually not participating in the photoinduced redox processes. The quantum yield of Fe(II) formation ΦFe(II) decreases significantly with increased wavelength of the incident radiation, and is slightly influenced by the peripheral groups R of the 4-R-benacen-ligands.http://dx.doi.org/10.1155/IJP/2006/78234
spellingShingle Jozef Šima
Mário Izakovič
Marián Žitňanský
Mechanism of deactivation processes of excited iron(III) thiocyanato complexes with benacen-type ligands
International Journal of Photoenergy
title Mechanism of deactivation processes of excited iron(III) thiocyanato complexes with benacen-type ligands
title_full Mechanism of deactivation processes of excited iron(III) thiocyanato complexes with benacen-type ligands
title_fullStr Mechanism of deactivation processes of excited iron(III) thiocyanato complexes with benacen-type ligands
title_full_unstemmed Mechanism of deactivation processes of excited iron(III) thiocyanato complexes with benacen-type ligands
title_short Mechanism of deactivation processes of excited iron(III) thiocyanato complexes with benacen-type ligands
title_sort mechanism of deactivation processes of excited iron iii thiocyanato complexes with benacen type ligands
url http://dx.doi.org/10.1155/IJP/2006/78234
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AT marianzitnansky mechanismofdeactivationprocessesofexcitedironiiithiocyanatocomplexeswithbenacentypeligands