Synthesis, crystal structures and fluorescence properties of dinuclear Tb(III) and Sm(III) complexes with 2,4,6-tri(2-pyridyl)-1,3,5-triazine and halogenated benzoic acid

• Three ternary lanthanide complexes with o-BrBA, o-ClBA and TPTZ were synthesized.
• Three dinuclear crystals have different structures.
• The luminescence spectra, lifetimes and quantum efficiencies were investigated.
• The emission quantum efficiencies of three terbium complexes were all above 21%.

Three ternary lanthanide complexes with o-bromobenzoic (o-BrBA), o-chlorobenzoic acid (o-ClBA) and 2,4,6-tri(2-pyridyl)-s-triazine (TPTZ) have been synthesized. These complexes were characterized by elementary analysis, UV absorption spectroscopy and IR spectroscopy. The crystal structures of [Tb2(TPTZ)2(o-BrBA)4(NO3)2(H2O)2] (1), [Tb2(TPTZ)2(o-ClBA)3(NO3)2(H2O)3]·o-ClBA·C2H5OH·2H2O (2) and [Sm2(TPTZ)2(o-ClBA)4(NO3)2(H2O)2] (3) were determined by single-crystal X-ray diffraction, and they were all dinuclear complexes with the characteristic of triclinic and P-1P-1 space group. The crystals 1 and 3 were isostructural, whose center ions were bridged by μ2-o-BrBA−/μ2-o-ClBA− ions and the coordinate number of the central metal ions were nine, composed by a η3-TPTZ, two bridging bidentates and one monodentate o-BrBA (o-ClBA) ligand, a bidentate NO3− and a coordinated water molecule. But the structure of complex 2 was asymmetric and the two Tb(III) ions have different coordination surroundings. Furthermore, the luminescence spectra and luminescence lifetimes of three crystals were then measured. Besides, the two Tb(III) complexes exhibit high emission quantum efficiencies.

Three ternary lanthanide complexes of Tb(III), Sm(III) with o-BrBA (o-ClBA) and TPTZ are synthesized, and their crystal structures and luminescence properties have been determined. The emission quantum efficiencies of the two terbium complexes are both above 21%.Figure optionsDownload as PowerPoint slide