Chalcone Based Colorimetric Sensor for Anions: Experimental and TD-DFT Study

The interactions between sensor chalcone of 3-(4-hydroxy-3-methoxyphenyl)-1-phenyl-2-propen-1-one (1) and anions (F-, Cl-, Br-, CN-, CO32-, and SO42-) have been experimentally and TD-DFT theoretically investigated. Sensor (1) showed a naked-eye detectable color change from yellow to red upon addition of F-, CO32-, CN-, and SO42- anions in DMSO, whereas no significant color change was observed upon addition of Cl- and Br- anions. The interaction models were predicted by optimizing (1)-anion complex using DFT/B3LYP method. Optimized (1)-anion complexes showed that sensor (1) was deprotonated by CO32-, CN-, F-, and SO42-. The formation of deprotonated sensor (1)(-) was responsible for the colorimetric signaling. Absorption spectra of neutral and deprotonated sensor were calculated using TD-DFT method. The calculated spectra were in good agreement with experimental results.