Dual ion selective fluorescence sensor with potential applications in sample monitoring and membrane sensing

A new sensing functionalized chemosensor 3-hydroxy-2-(1H-indol-3-yl)-4H-chromen-4-one (M1) was readily prepared in facile reaction conditions and explored its sensing nature response towards metal ions in semi-aqueous medium. The chemosensor M1 exhibited high selective and sensitive fluorescence turn “off-on” response for Al3+ and Zn2+ ions in the existence of several metal ions and the changes are enabled for naked-eye detection. These high selectivity expressed by high binding constants 2.62 × 104 (Al3+) and 1.92 × 104 M−1 (Zn2+) calculated by the Benesi-Hildebrand equation based on the emission studies. The binding strategy was also supported by 1H NMR titration