An effective long-wavelength fluorescent sensor for Cu based on dibenzylidenehydrazine-bridged biphenylacrylonitrile.

Although numerous fluorescence sensors for Cu have been presented, a long-wavelength sensor in aqueous media has rarely been reported as expected due to practical application requirements. In this work, a novel AIE molecule (DHBB) containing two biphenylacrylonitrile units bridged by dibenzylidenehydrazine was prepared. It possessed the merits of long-wavelength emission, good emission in aqueous media, and multiple functional groups for binding Cu. It exhibited good sensing selectivity for Cu among all kinds of tested metal ions. The detection limit was as low as 1.08 × 10 M. The sensing mechanism was clarified as 1:1 stoichiometric ratio based on the binding cooperation of O and N functional groups of DHBB. The selective sensing ability for Cu remained stable at pH = 5-9 and was influenced little by other metal ions. The Cu sensing ability of DHBB was applied in real samples with 96% recovery rate. The bio-imaging experiment of living cells suggested that DHBB possessed not only good bio-imaging performance but also sensing ability for Cu in living environments. This work suggested the good application prospect of DHBB to sense Cu in real samples and living environment.