title: A highly selective two-photon fluorescent probe for detection of cadmium(II) based on intramolecular electron transfer and its imaging in living cells.
abstract: A new quinoline-based probe was designed that shows one-photon ratiometric and two-photon off-on changes upon detecting Cd(2+) . It exhibits fluorescence emission at 407 nm originating from quinoline groups in Tris-HCl (25 mM, pH 7.40), H2 O/EtOH (8:2, v/v). Coordination with Cd(2+) causes quenching of the emission at 407 nm and simultaneously yields a remarkable redshift of the emission maximum to 500 nm with an isoemissive point at 439 nm owing to an intramolecular charge-transfer mechanism. Thus, dual-emission ratiometric measurement with a large redshift (Δλ=93 nm) and significant changes in the ratio (F500 /F439 ) of the emission intensity (R/R0 up to 27) is established. Moreover, the sensor H2 L displays excellent selectivity response, high sensitive fluorescence enhancement, and strong binding ability to Cd(2+). Coordination properties of H2 L towards Cd(2+) were fully investigated by absorption/fluorescence spectroscopy, which indicated the formation of a 2:1 H2 L/Cd(2+) complex. All complexes were characterized by X-ray crystallography, and TD-DFT calculations were performed to understand the origin of optical selectivity shown by H2 L. Two-photon fluorescence microscopy experiments have demonstrated that H2 L could be used in live cells for the detection of Cd(2+).
authors.affiliation: Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu Province and State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (P. R. China), Fax: (+86) 931-8912582.
authors.forename: Zhaohua
authors.initials: Z
authors.lastname: Shi
authors.forename: Qingxin
authors.initials: Q
authors.lastname: Han
authors.forename: Lizi
authors.initials: L
authors.lastname: Yang
authors.forename: Huan
authors.initials: H
authors.lastname: Yang
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Tang
authors.forename: Wei
authors.initials: W
authors.lastname: Dou
authors.forename: Zhiqi
authors.initials: Z
authors.lastname: Li
authors.forename: Yange
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yongliang
authors.initials: Y
authors.lastname: Shao
authors.forename: Liping
authors.initials: L
authors.lastname: Guan
authors.forename: Weisheng
authors.initials: W
authors.lastname: Liu
mesh_terms: D002104:Cadmium / Q000737:chemistry*; D045744:Cell Line, Tumor; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry; D018360:Crystallography, X-Ray; D004579:Electron Transport; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D008856:Microscopy, Fluorescence; D008968:Molecular Conformation; D017785:Photons; D011789:Quantum Theory; D011804:Quinolines / Q000737:chemistry; D013050:Spectrometry, Fluorescence
chemical_list: D056831:Coordination Complexes; D005456:Fluorescent Dyes; D011804:Quinolines; D002104:Cadmium; C037219:quinoline
keywords: cadmium; fluorescence; intramolecular electron transfer; ratiometry; semirigid structures