title: Fluorogenic Zn(II) and chromogenic Fe(II) sensors based on terpyridine-substituted tetraphenylethenes with aggregation-induced emission characteristics.
abstract: Terpyridine-containing tetraphenylethenes (TPEs) are synthesized and their optical and metal sensing properties are investigated. They are practically nonluminescent in the solution state but become highly emissive as nanoparticle suspensions in poor solvents or thin films in the solid state, demonstrating a novel phenomenon of aggregation-induced emission (AIE). The emission of the nanoaggregates of TPEs is pH-sensitive: it is decreased and eventually quenched upon protonation of their terpyridine units because of their AIE nature. The TPEs can work as "turn-off" fluorescent chemosensors for metal ions and display different fluorescence responses to various metal ions. A characteristic red shift in the emission spectra is observed in the presence of Zn(2+), which facilitates the discrimination of Zn(2+) from other metal ions. Because of the metal-to-ligand-charge-transfer process, terpyridine-substituted TPEs display an obvious magenta color upon selectively binding with Fe(2+), allowing a rapid identification of Fe(2+) in the aqueous media by naked eyes.
authors.affiliation: Department of Chemistry, Nano Science and Technology Program, Institute of Molecular Functional Materials, The Hong Kong University of Science & Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Yuning
authors.initials: Y
authors.lastname: Hong
authors.forename: Sijie
authors.initials: S
authors.lastname: Chen
authors.forename: Chris Wai Tung
authors.initials: CW
authors.lastname: Leung
authors.forename: Jacky Wing Yip
authors.initials: JW
authors.lastname: Lam
authors.forename: Jianzhao
authors.initials: J
authors.lastname: Liu
authors.forename: Nai-Wen
authors.initials: NW
authors.lastname: Tseng
authors.forename: Ryan Tsz Kin
authors.initials: RT
authors.lastname: Kwok
authors.forename: Yong
authors.initials: Y
authors.lastname: Yu
authors.forename: Zhengke
authors.initials: Z
authors.lastname: Wang
authors.forename: Ben Zhong
authors.initials: BZ
authors.lastname: Tang
mesh_terms: D005030:Ethylenes / Q000737:chemistry*; D005296:Ferrous Compounds / Q000032:analysis*; D005456:Fluorescent Dyes / Q000737:chemistry*; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D015032:Zinc / Q000032:analysis*
chemical_list: D005030:Ethylenes; D005296:Ferrous Compounds; D005456:Fluorescent Dyes; D011725:Pyridines; D019904:Polymethyl Methacrylate; C036216:ethylene; D015032:Zinc; C023666:pyridine