An effective dual sensor for Cu2+ and Zn2+ with long-wavelength fluorescence in aqueous media based on biphenylacrylonitrile Schiff-base

Although some sensors for Cu 2+ and Zn 2+ had been reported, the sensor with long-wavelength emission in aqueous media for in-situ detecting Cu 2+ and Zn 2+ was always expected. Herein, a biphenylacrylonitrile Schiff-base ( OPBS ) with large aromatic conjugated system was designed and synthesized in yield of 82%. OPBS possessed excellent long-wavelength fluorescence at 550–750 nm in aqueous media, which selectively response to sense Cu 2+ with quenched fluorescence and Zn 2+ with chromotropic fluorescence from red to yellow. The detection of Cu 2+ and Zn 2+ were realized without mutual interference in their coexistence system by means of the assistance of ATP. The detection limits were 2.3 × 10 −7 M for Cu 2+ and 1.8 × 10 −6 M for Zn 2+ , respectively. The sensing mechanism was elucidated by binding MS spectra, fluorescence Job’s plot and 1 H NMR spectra. Moreover, OPBS exhibited good bioimaging performance and the in-situ sensing abilities for Cu 2+ and Zn 2+ in living cells, suggesting the application potential for detecting Cu 2+ and Zn 2+ in both vitro assay and vivo environment.