A simple hydrazone as a fluorescent turn-on multianalyte (Al3+, Mg2+, Zn2+) sensor with different emission color in DMSO and resultant Al3+ complex as a turn-off sensor for F− in aqueous solution

A novel pyrazine hydrazone 1 has been designed and synthesized, which acts as a multiprobe for selective detection of Al³⁺, Mg²⁺, and Zn²⁺ in DMSO solution based on fluorescent enhancement with three different emission colors. The higher affinity of 1 toward Al³⁺ and Zn²⁺ compared with Mg²⁺ facilitates the establishment of a simple ratiometric fluorescent method for the detection of Al³⁺ and Zn²⁺ based on the 1 + Mg²⁺ system. Conversely, probe 1 selectively recognized Al³⁺ in DMSO-H₂O cosolvent with a turn-on response, and the resultant 1 + Al³⁺ complex could determine F⁻ via a fluorescence quenching signal. In addition, the probe is applied for imaging of Al³⁺ and F⁻ in living cells.