A highly selective fluorescent sensor for mercury ion (II) based on azathia‐crown ether possessing a dansyl moiety

An intramolecular charge transfer (ICT) fluorescent sensor 1 using a dansyl moiety as the fluorophore and an azathia-crown ether as the receptor was designed, synthesized and characterized. The ions-selective signaling behaviors of the sensor 1 were investigated in CH3CN-H2O (1:1, v/v) by fluorescence spectroscopy. It exhibited remarkable fluorescence quenching upon addition of Hg2+, which was attributed to the 1:1 complex formation between 1 and Hg2+, while other selected metal ions induced basically no spectral changes. The sensor 1 showed a rapid and linear response towards Hg2+ in the concentration range from 5.0 × 10−7 to 1.0 × 10−5 mol L−1 with the detection limit of 1.0 × 10−7 mol L−1. Furthermore, the whole process could be carried out in a wide pH range of 2.0–8.0 and was not disturbed by other metal ions. Thus, the sensor 1 was used for practical determination of Hg2+ in different water samples with satisfactory results. Copyright © 2010 John Wiley & Sons, Ltd.