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

A new complex of {[Eu-2(2-BrBA)(6)(2,2'-bpy)(2)](2)center dot CH3CH2OH center dot H2O} (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 (1) over bar space group, with a=1.17196(4) nm, b=2.36142(9) nm, c=2.59151(9) nm, alpha=113.266(2)degrees, beta=101.100(2)degrees, and gamma=94.400(2)degrees. 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 D-5(0)-> F-7(0), D-5(0)-> F-7(1), D-5(0)-> F-7(2), D-5(0)-> F-7(3), and D-5(0)-> F-7(4) transition emissions of the Eu(III) ion, respectively.