resumo
Density functional theory/time-dependent density functional theory (DFT/TD-DFT) calculations were performed on a series of europium(III) complexes of 4,7-disubstituted-1,10-phenanthroline ligands (phen-X) of general formula Eu(TTA)(3)(phen-X) (where TTA stands for thenoyltrifluoroacetonato and X = H, CH(3), OCH(3), Cl, Br, CO(2)Et, C(6)H(5), C(4)HOCH(3) and C(4)H(3)OCH(3)). The effect of such substitution on the structural, electronic and photophysical properties is established. Absorption spectra calculations show that different phen substituents have different effects on absorption peak positions and on transition characters while only substituent's influence via extended p-conjugation of the phen ligand can effectively tune the triplet state. Considering the Delta E(ISC) and Delta E(ET) values, the luminescent (5)D(0) state of the Eu(3+) ion can be efficiently populated in most complexes. The exceptions are the complexes with CO(2)Et and C(4)H(3)OCH(3) groups.
palavras-chave
FUNCTIONAL RESPONSE THEORY; TRIPLET-STATE ENERGY; RARE-EARTH COMPLEXES; CRYSTAL-STRUCTURE; LUMINESCENT PROPERTIES; LANTHANIDE COMPLEXES; EXCITATION-ENERGIES; ELECTROLUMINESCENCE PROPERTIES; AROMATIC LIGANDS; QUANTUM YIELD
categoria
Chemistry
autores
Nolasco, MM; Vaz, PD; Carlos, LD
nossos autores
Luís Carlos
Professor Catedrático
Mariela Martins Nolasco
Investigador AuxiliarGrupos
G2 - Materiais Fotónicos, Eletrónicos e Magnéticos
G6 - Materiais Virtuais e Inteligência Artificial
agradecimentos
The authors acknowledge financial support from the Fundacao para a Ciencia e a Tecnologia (FCT_PTDC/CTMNAN/112168/2009) and Laboratorio Associado CICECO for granting access to the Flamingo multi-processor cluster. MN (SFRH/BPD/32103/2006) also acknowledges FCT for a research grant. MN would also like to express their acknowledgements to Professor Ricardo Luiz Longo from Departamento de Quimica Fundamental-Universidade Federal de Pernambuco for their helpful knowledge transfer which contributed to improve this article.