Sistemas Trinucleares Contendo Ãons LantanÃdeos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Aiming to develop new ligands capable to coordinate most of one lanthanide ions, this work shows the synthesis of trinuclear systems for photonics applications and characterization by elemental analysis, spectroscopic methods (infrared, electronic absorption and NMR of 1H and 13C). A particular study, about the new compounds synthetized, shows the substitution need of water molecules, from first coordination sphere, for organic ligands. After substitution for heterobi(tri)aryl ligands (bipyridine, phenanthroline and terpyridine), reported in the literature, the complexes present their spectroscopy properties promising for desired applications. The elemental analysis data (experimental and theory) from complexes shows great consonance; confirming minimal formula proposed. The electronic absorption and infrared data shows that ligands are coordinated to lanthanide ions. The luminescence spectroscopy presents the characteristics transition of Eu3+ and Tb3+. For the Gd3+ complexes, the triplet states are determinate by phosphorescence measurement. From energy diagram, that estimate triplets levels, it is possible to understand some experimental phenomenon observed, as weak luminescence for precursor complex (without heterocyclics ligands), as will ligands emission in terbium complexes. The parameters R02 and the intensities (Ωλ), determinate that complex [Eu3(TRI)(bipy)6(H2O)6]Cl6 shows a strong ligand field (major blend Jâs), major covalence factor and minor perturbation in complexation effect (β-diketone), when compared with [Eu3(TRI)(phen)6(H2O)6]Cl6 and [Eu3(TRI)(terpy)6]Cl6. The synthetized complexes shows high values of quantum yield in ethanolic environment; 50% for complex EuTRIbipy, 26% EuTRIterpy and 5,6% for EuTRIphen

ASSUNTO(S)

quantum yield lanthanide ion quimica trinuclear system rendimento quÃntico Ãons lantanÃdeos sistemas trinucleares

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