Synthesis and photoluminescent properties of four novel trinuclear europium complexes based on two tris-β-diketones ligands

Four novel trinuclear europium complexes with two tris-beta-diketones ligands have been synthesized, and the chemical structures of ligands and complexes were characterized by Fr-IR, UV-vis, H-1 NMR, C-13 NMR, XRD, ESI-MS, and element analysis. The potoluminescent properties of trinuclear complexes in solid and THF solution were investigated. All trinuclear complexes exhibited strong relative luminescent intensity and long luminescent lifetime. Meanwhile, the results of lifetime decay curves indicated that only one chemical environment existed around the europium ion. The intrinsic luminescent quantum yields (Phi(LN)) and experimental intensity parameters of trinuclear complexes were obtained based on the emission spectra and luminescent lifetime of D-5(0) excited state for europium ion. All trinuclear europium complexes exhibited relative high intrinsic luminescent yield and intensity parameters. Especially, due to the contribution of addition two europium lumophors in trinuclear europium complexes, the trinuclear complexes containing TTA exhibited much longer lifetime and higher intrinsic quantum yield than mononuclear europium complex Eu(TTA)(3)phen. (C) 2011 Elsevier Ltd. All rights reserved.