A biacylhydrazone-based chemosensor for fluorescence ‘turn-on’ detection of Al3+ with high selectivity and sensitivity

A simple Al3+ fluorescent chemosensor (1) based on diacylhydrazone has been designed and synthesized by the condensation reaction of 2-hydroxy naphthaldehyde and metaphthalic hydrazide. The chemosensor 1 displays a specific and sensitive response to Al3+ over other cations in DMSO solution. Upon the addition of DMSO solution of Al3+, the sensor 1 shows an immediate fluorescence ‘turn-on’ response and emitting strong blue emission with visible color change from colorless to green. The fluorescence quantum yield enhanced from 7.24% to 48.68%. Meanwhile, the fluorescence and UV absorption spectra detection limits of the chemosensor 1 for Al3+ were 2.0 × 10−7 M and 5.6 × 10−7 M respectively, indicating the high sensitivity of 1 to Al3+. Furthermore, test strips based on 1 were fabricated, which could be used as a convenient test kit for the detection of Al3+ and an efficient Al3+ controlled fluorescent security display materials.