Synthesis and Luminescence Properties of Two Novel Lanthanide (III) Perchlorate Complexes with Bis(benzoylmethyl) Sulfoxide and Benzoic Acid

Two novel ternary rare earth complexes of Tb (III) and Dy(III) perchlorates with bis(benzoylmethyl) sulfoxide (L) and benzoic acid (L') had been synthesized and characterized by elemental analysis, coordination titration analysis, molar conductivity, IR, TG-DSC, 1HNMR and UV spectra. The results indicated that the composition of these complexes was REL5L'(ClO(4))(2)center dot nH(2)O (RE= Tb(III), Dy(III); L=C(6)H(5)COCH(2)SOCH(2)COC(6)H(5), L'=C(6)H(5)COO; n=6,8). The fluorescence spectra illustrated that the ternary rare earth complexes presented stronger fluorescence intensities, longer lifetimes and higher fluorescence quantum efficiencies than the binary rare earth complexes REL(5)center dot(ClO(4))(3)center dot 2H(2)O. After the introduction of the second ligand benzoic acid group, the relative fluorescence emission intensities and fluorescence lifetimes of the ternary complexes REL5L'(ClO(4))(2)center dot nH(2)O (RE= Tb(III), Dy (III)) enhanced more obviously than the binary complexes. This indicated that the presence of both organic ligands bis (benzoylmethyl) sulfoxide and the second ligand benzoic acid could sensitize fluorescence intensities of rare earth ions, and the introduction of benzoic acid group was resulted in the enhancement of the fluorescence properties of the ternary rare earth complexes. The phosphorescence spectra were also discussed.