title: Luminescent pH sensor of a novel imidazole-containing hexanuclear Ru(II) polypyridyl complex.
abstract: Hexapodal ligand H6L containing imidazole rings has been prepared by the reaction of 1,10-phenanthroline-5,6-dione with 1,2,3,4,5,6-hexakis[(3-formylphenoxy)methyl]benzene. The Ru(II) polypyridyl complex [{Ru(bpy)2}6(μ6-H6L)](PF6)12 (bpy=2,2'-bipyridine) has been synthesized by the reaction of Ru(bpy)2Cl2·2H2O with ligand H6L. The pH effects on the UV-vis absorption and emission spectra of the complex have been studied. The ground- and excited-state ionization constants of the acid-base equilibria have been calculated according to the absorbance and emission data. The complex acts as an off-on-off luminescent pH sensor through two successive deprotonation processes of imidazole rings, with a maximum on-off ratio of 5 in buffer solution.
authors.affiliation: College of Chemistry and Chemical Engineering, Qujing Normal University, Qujing 655011, PR China. chengfx2013@163.com
authors.forename: Feixiang
authors.initials: F
authors.lastname: Cheng
authors.forename: Ning
authors.initials: N
authors.lastname: Tang
authors.forename: Jishu
authors.initials: J
authors.lastname: Chen
authors.forename: Guang
authors.initials: G
authors.lastname: Chen
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000737:chemistry*; D049449:Luminescence; D010618:Phenanthrolines / Q000737:chemistry; D012428:Ruthenium / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D007093:Imidazoles; D010618:Phenanthrolines; C037153:1,10-phenanthroline-5,6-dione; D015082:2,2'-Dipyridyl; C029899:imidazole; D012428:Ruthenium
keywords: Emission; Hexapodal ligand; Ru(II) complex; UV–vis absorption; pH sensor