Theoretical study of coumarin derivatives as chemosensors for fluoride anion

The interactions between chemosensor, coumarin derivative (1), and F−, Cl−, Br−, NO 3 - , AcO−, and H 2 PO 4 - anions have been theoretically investigated at the B3LYP/6-31G(d,p) level with the BSSE correction. It turned out that the unique selectivity of 1 for F− is ascribed to its ability of deprotonating the amido group of host sensor. The intermolecular proton transfer (IPT) causes the colorimetric signaling of 1 for F−. The deprotonated anion 1− is formed for the deprotonation process of chemosensor. The study of substituent effects suggest that both electron-donating (–CH3 and –OCH3,) and electron-withdrawing (–NO2, –CN, and –COCH3) substituted derivatives are expected to be promising candidates for chromogenic fluorescent F− chemosensors, except the electron-donating –N(CH3)2 substituted derivative does not suit to be a chromogenic F− chemosensor.