title: Selective anion sensing by a ruthenium(II)-bipyridyl-functionalized tripodal tris(urea) receptor.
abstract: A tripodal tris(urea) ligand with 2,2'-bipyridyl (bpy) substituents (L) has been designed and synthesized, which coordinates with three equivalents of Ru(bpy)(2)Cl(2)·2H(2)O, followed by treatment with NH(4)PF(6), to afford the anion receptor [(bpy)(6)Ru(3)L](PF(6))(6) (1). The anion-binding behavior of the ligand L and the Ru(II)-bpy functionalized receptor 1 toward different anions was investigated by (1)H NMR (for L and 1), fluorescence, and UV-vis spectroscopy (for 1). Both compounds showed selective recognition of SO(4)(2-) or H(2)PO(4)(-) ions in the 1:1 binding mode in the NMR studies. The Ru(II) complex 1 displayed the metal-to-ligand charge transfer emission at 600 nm, which was quenched on addition of the sulfate and dihydrogen phosphate ions. Quantitative fluorescence titration experiments were carried out and the stability constants (log K) of the complex 1 with SO(4)(2-) and H(2)PO(4)(-) ions were obtained to be 4.73 and 4.69 M(-1) (1:1 binding mode), respectively.
authors.affiliation: State Key Laboratory for Oxo Synthesis & Selective Oxidation, Lanzhou Institute of Chemical Physics, CAS, Lanzhou 730000, China.
authors.forename: Yongjing
authors.initials: Y
authors.lastname: Hao
authors.forename: Peiju
authors.initials: P
authors.lastname: Yang
authors.forename: Shaoguang
authors.initials: S
authors.lastname: Li
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Huang
authors.forename: Xiao-Juan
authors.initials: XJ
authors.lastname: Yang
authors.forename: Biao
authors.initials: B
authors.lastname: Wu
mesh_terms: D015082:2,2'-Dipyridyl / Q000138:chemical synthesis* / Q000737:chemistry; D000838:Anions; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D015336:Molecular Probe Techniques; D015394:Molecular Structure; D012428:Ruthenium / Q000737:chemistry*; D014508:Urea / Q000737:chemistry*
chemical_list: D000838:Anions; D008024:Ligands; D015082:2,2'-Dipyridyl; D012428:Ruthenium; D014508:Urea