Highly Selective Sensing of Li+ in H2O/CH3CN via Fluorescence ‘Turn-on’ Response of a Coumarin-Indole Linked Dyad: an Experimental and Theoretical Study

Abstract

A coumarin-indole dyad, N-((7-hydroxy-2-oxo-2H-chromen-4-yl)methyl)-1H-indole-2-carboxamide has been synthesized and characterized by 1H-NMR and 13C-NMR. Effect of various metal ions on fluorescent behavior was also studied. The synthesized compound showed remarkable specificity towards Li+ in organo-aqueous medium over other metal ions. Coordination of the compound with Li+ induces a turn-on fluorescence response. The sensor exhibited good binding constant and low detection limit towards Li+. Experimental results have been verified with Density Functional Theory and Time Dependent Density Functional Theory calculations.