PHOTOPHYSICAL AND REDOX PROPERTIES OF NEW MONO- AND BI-METALLIC ANTHRACENE-FUNCTIONALISED CYCLOPENTADIENYL DERIVATIVES OF RHODIUM AND IRIDIUM
| Autor: | Cicogna F., (1)(2) G. Ingrosso, (1) Q. Lunardi, (1) F. Marchetti (1) C. Pinzino (3) |
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| Jazyk: | angličtina |
| Rok vydání: | 2008 |
| Předmět: | |
| Zdroj: | XVII Congresso Nazionale di Chimica Industriale, pp. EGC-P10, Genova, 30/06/2008-03/07/2008 info:cnr-pdr/source/autori:Cicogna F., (1)(2) G. Ingrosso, (1) Q. Lunardi, (1) F. Marchetti (1) C. Pinzino (3)/congresso_nome:XVII Congresso Nazionale di Chimica Industriale/congresso_luogo:Genova/congresso_data:30%2F06%2F2008-03%2F07%2F2008/anno:2008/pagina_da:EGC-P10/pagina_a:/intervallo_pagine:EGC-P10 |
| Popis: | Great attention is currently devoted to the synthesis and study of the photochemical, photophysical, and redox properties of transition metal complexes with the aim of assembling new systems capable to exhibit useful functions induced by light absorption or by electron transfer processes. The transition metal-?5-cyclopentadienyl system undergoes easily one-electron oxidation or reduction and this makes such a moiety promising for the design of new molecular devices. Indeed, during the last years we have observed that when it is connected to a sub-unit acting as an antenna it is capable to modify the physical properties of the antenna (radiation emission, charge transfer, redox behaviour, etc.). The electronic properties of these complexes are markedly dependent upon the nature of the spacer that separates the fluorophore and the cyclopentadienyl ring, the flexibility of the spacer being playing an important role in determining the entity of the electronic interaction between the sub-units. We have now extended these studies to the mono- and bi-metallic derivatives of rhodium(I) and iridium(I) in which the fluorophoric unit is directly connected to the cyclopentadienyl ring thus giving rise to previously unknown rigid and conjugated ligands. We have studied how the active sites, i.e. the cyclopentadienyl-metal systems and the fluorophore interact under photophysical, electrochemical, and chemical activation conditions. The UV- Visible spectra of all compounds are indicative of strong interactions between the fluorophoric sub-unit and the metal-Cp moiety. When photoexicited, the above derivatives are poorly luminescent or not at all, all data being in line with the hypothesis that the quenching of the fluorescence can be due to an intramolecular electron transfer process. Similarly, the EPR study of the one- electron oxidation of all compounds shows that in the resulting cation-radicals the unpaired electron spin delocalization interest the whole complex, thus being indicative again of the existence of a strong interaction between the sub-units. The possible implication of this kind of compounds in the design of new molecular devices is deiscussed. |
| Databáze: | OpenAIRE |
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