title: A small-molecular europium complex with anion sensing sensitivity.
abstract: A novel small-molecular europium(III) complex with quinoline derivative has been designed and prepared for anion recognition. This Eu(3+) complex displays striking emission changes at 616 nm in response to NO(3)(-) and Cl(-). What's more, the anion-selective luminescence enhancement is easily detected by the naked eye. UV, luminescence titration experiments and the Job plot analysis revealed that the ligand can form stable 1 : 1 complexes with Eu(NO(3))(3) or EuCl(3) in CH(3)CN; log K = 7.10 and 6.76 (295 K), respectively. The crystal structure shows that three oxygen atoms and one nitrogen atom of the ligand are approximately coplanar and wrap around the Eu(3+) ion through a semicircle-shaped coordination structure and some unoccupied sites of the central europium ions are available for guest anions in the complexes. Thus, three nitrate ions are located in the gap of the semicircle. It is supposed that the mechanism of luminescence enhancement is of NO(3)(-) or Cl(-) anions squeezing out solvent molecules from the inner coordination sphere.
authors.affiliation: Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, P. R. China.
authors.forename: Jianwei
authors.initials: J
authors.lastname: Wang
authors.forename: Jiang
authors.initials: J
authors.lastname: Wu
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Chen
authors.forename: Haiping
authors.initials: H
authors.lastname: Wang
authors.forename: Yiran
authors.initials: Y
authors.lastname: Li
authors.forename: Weisheng
authors.initials: W
authors.lastname: Liu
authors.forename: Hao
authors.initials: H
authors.lastname: Tian
authors.forename: Ting
authors.initials: T
authors.lastname: Zhang
authors.forename: Jun
authors.initials: J
authors.lastname: Xu
authors.forename: Yu
authors.initials: Y
authors.lastname: Tang
mesh_terms: D002712:Chlorides / Q000737:chemistry*; D005063:Europium / Q000737:chemistry*; D008024:Ligands; D049449:Luminescence; D009682:Magnetic Resonance Spectroscopy; D009566:Nitrates / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D002712:Chlorides; D008024:Ligands; D009566:Nitrates; D005063:Europium