title: Synthesis and spectroscopic behavior of highly luminescent Eu(3+)-dibenzoylmethanate (DBM) complexes with sulfoxide ligands.
abstract: In 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 Eu(3+)-beta-diketonate complexes show characteristics narrow bands arising from the 5D0-->7F(J) (J=0-4) transitions, which are split according to the selection rule for C(n), C(nv) or C(s) site symmetries. The experimental Judd-Ofelt intensity parameters (Omega2 and Omega4), radiative (A(rad)) and non-radiative (A(nrad)) decay rates, and R02 for the europium complexes have been determined and compared. The highest value of Omega2 (61.9x10(-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 (eta) 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)3H2O], 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.
authors.affiliation: Departamento de Química Fundamental, Instituto de Química da Universidade de São Paulo, 05508-900 São Paulo, SP, Brazil.
authors.forename: E
authors.initials: E
authors.lastname: Niyama
authors.forename: H F
authors.initials: HF
authors.lastname: Brito
authors.forename: M
authors.initials: M
authors.lastname: Cremona
authors.forename: E E S
authors.initials: EE
authors.lastname: Teotonio
authors.forename: R
authors.initials: R
authors.lastname: Reyes
authors.forename: G E S
authors.initials: GE
authors.lastname: Brito
authors.forename: M C F C
authors.initials: MC
authors.lastname: Felinto
mesh_terms: D005063:Europium / Q000737:chemistry*; D008024:Ligands; D008163:Luminescent Measurements; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010777:Photochemistry; D012451:Safrole / Q000031:analogs & derivatives* / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013696:Temperature; D014867:Water
chemical_list: C504558:Eu(III)-dibenzoylmethanate; D008024:Ligands; D009942:Organometallic Compounds; D014867:Water; D005063:Europium; D012451:Safrole; C005746:sulfoxide