Synthesis, crystal structure and fluorescence of a new europium complex with 2-bromobenzoate and 2,2'-bipyridine

Abstract A new complex of {[Eu 2 (2-BrBA) 6 (2,2′-bpy) 2 ] 2 ·CH 3 CH 2 OH·H 2 O} (2-BrBA=2-bromobenzoate; 2,2′-bpy=2,2′-bipyridine) was prepared by solvent method and characterized with X-ray single-crystal diffraction, IR spectroscopy, UV spectroscopy, and fluorescence spectroscopy. The complex crystallized in triclinic crystal system, P ī space group, with a =1.17196(4) nm, b =2.36142(9) nm, c =2.59151(9) nm, α =113.266(2)°, β =101.100(2)°, and γ =94.400(2)°. Two independent dinuclear molecules were contained in the asymmetric unit. The two molecules were similar to each other. Each Eu(III) ion was nine-coordinated with seven oxygen atoms from five 2-BrBA ligands and two nitrogen atoms from 2,2′-bpy molecule. The carboxylate groups acted as bidentate-chelating, bidentate-bridging and chelating-bridging coordination modes. The complex adopted a distorted monocapped square-antiprism coordination geometry. Five peaks at 579, 591, 613, 652, and 697 nm appeared in the fluorescence spectrum, corresponding to 5 D 0 → 7 F 0 , 5 D 0 → 7 F 1 , 5 D 0 → 7 F 2 , 5 D 0 → 7 F 3 , and 5 D 0 → 7 F 4 transition emissions of the Eu(III) ion, respectively.