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: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2006-01-01
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| Series: | International Journal of Photoenergy |
| Online Access: | http://dx.doi.org/10.1155/IJP/2006/78234 |
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| Summary: | 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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| ISSN: | 1110-662X 1687-529X |