title: Experimental and theoretical approaches toward anion-responsive tripod-lanthanide complexes: mixed-donor ligand effects on lanthanide complexation and luminescence sensing profiles.
abstract: A new series of tripods were designed to form anion-responsive, luminescent lanthanide complexes. These tripods contain pyridine, thiazole, pyrazine, or quinoline chromophores combined with amide carbonyl oxygen and tertiary nitrogen atoms. Crystallographic and EXAFS studies of the 10-coordinated tripod-La(NO(3))(3) complexes revealed that each La(3+) cation was cooperatively coordinated by one tetradentate tripod and three bidentate NO(3)(-) anions in the crystal and in CH(3)CN. Quantum chemical calculations indicated that the aromatic nitrogen plays a significant role in lanthanide complexation. The experimentally determined stability constants of complexes of the tripod with La(NO(3))(3), Eu(NO(3))(3), and Tb(NO(3))(3) were in good agreement with the theoretically calculated interaction energies. Complexation of each tripod with lanthanide triflate gave a mixture of several lanthanide complex species. Interestingly, the addition of a coordinative NO(3)(-) or Cl(-) anion to the mixture significantly influenced the lanthanide complexation profiles. The particular combination of tripod and a luminescent Eu(3+) center gave anion-selective luminescence enhancements. Pyridine-containing tripods exhibited the highest NO(3)(-) anion-selective luminescence and thus permit naked-eye detection of the NO(3)(-) anion.
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Kataoka
authors.forename: Dharam
authors.initials: D
authors.lastname: Paul
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Miyake
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Yaita
authors.forename: Eisaku
authors.initials: E
authors.lastname: Miyoshi
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Mori
authors.forename: Shinya
authors.initials: S
authors.lastname: Tsukamoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tatewaki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Shinoda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsukube
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000838:Anions / Q000737:chemistry; D018360:Crystallography, X-Ray; D006571:Heterocyclic Compounds / Q000737:chemistry*; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008024:Ligands; D049449:Luminescence; D009682:Magnetic Resonance Spectroscopy; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000097:Acetonitriles; D000838:Anions; D006571:Heterocyclic Compounds; D028581:Lanthanoid Series Elements; D008024:Ligands