Produção Nacional
Revisado por pares
Synthesis and spectroscopic behavior of highly luminescent Eu3+–dibenzoylmethanate (DBM) complexes with sulfoxide ligands
2004; Elsevier BV; Volume: 61; Issue: 11-12 Linguagem: Inglês
10.1016/j.saa.2004.10.006
ISSN1873-3557
AutoresE. Niyama, Hermi F. Brito, M. Cremona, Ercules E. S. Teotônio, R. Reyes, G.E.S. Brito, M.C.F.C. Felinto,
Tópico(s)Luminescence Properties of Advanced Materials
ResumoIn this paper the synthesis, characterization and photoluminescent behavior of the [RE(DBM)3L2] complexes (RE = Gd and Eu) with a variety of sulfoxide ligands; L = benzyl sulfoxide (DBSO), methyl sulfoxide (DMSO), phenyl sulfoxide (DPSO) and p-tolyl sulfoxide (PTSO) have been investigated in solid state. The emission spectra of the Eu3+–β-diketonate complexes show characteristics narrow bands arising from the 5D0 → 7FJ (J = 0–4) transitions, which are split according to the selection rule for Cn, Cnv or Cs site symmetries. The experimental Judd–Ofelt intensity parameters (Ω2 and Ω4), radiative (Arad) and non-radiative (Anrad) decay rates, and R02 for the europium complexes have been determined and compared. The highest value of Ω2 (61.9 × 10−20 cm2) was obtained to the complex with PTSO ligand, indicating that Eu3+ ion is in the highly polarizable chemical environment. The higher values of the experimental quantum yield (q) and emission quantum efficiency of the emitter 5D0 level (η) for the Eu-complexes with DMSO, DBSO and PTSO sulfoxides suggest that these complexes are promising Light Conversion Molecular Devices (LCMDs). The lower value of quantum yield (q = 1%), for the hydrated complex [Eu(DBM)3(H2O)], indicates that the luminescence quenching occurs via multiphonon relaxation by coupling with the OH-oscillators from water molecule coordinated to rare earth ion. The pure red emission of the Eu-complexes has been confirmed by (x, y) color coordinates.
Referência(s)