A turn-on fluorescent sensor for highly selective recognition of Mg2+ based on new Schiff’s base derivative

• The receptor HL shows obviously enhancement of fluorescence intensity in the present of Mg2+.
• The detection limit of HL for Mg2+ could reach at 10−7 M level.
• HL showed a good selectivity to Mg2+ over other metal cations, especially Ca2+, which often responds together with Mg2+.

A new senser Isatin-3-(7′-Methoxychromone-3′-methylidene) hydrazone based on chromone Schiff base was synthesized to detect Mg2+. The complexation behavior of chemosensor with different metal ions in ethanolic solution was studied on UV–vis absorption spectra and fluorescent spectra. Results showed that the chemosensor HL displayed a 70-fold fluorescence enhancement upon the addition of Mg2+ due to the photo-induced electron transfer (PET) effect. On the other hand, metal ions except Mg2+ did not cause significant change in either the absorption or the fluorescence spectrum of HL. In addition, HL showed a good selectivity to Mg2+ over other metal cations, especially Ca2+, which often responds together with Mg2+. Therefore, HL can act as an efficient sensor for magnesium ion.

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