Dual Spectroscopic Responses of Pyridinium Hemicyanine Dyes to Anions

Abstract

AbstractThe absorption and fluorescence spectroscopic responses of three pyridinium hemicyanine dyes to anions F−, Cl−, Br−, I−, H2PO4−, HSO4− and OAc− were investigated. At lower concentrations of OAc− (less than 1 equiv.), both the absorption and the fluorescence intensities of 1–3 were more effectively changed than F− at identical concentrations. At higher concentrations of OAc− (more than 1 equiv.), the interaction was opposite for each compound. 1H NMR results indicated the interaction between 1, 2 or 3 and F− proceeded through hydrogen bonding. The results showed that these dyes are promising to develop dual fluorescence and chromogenic chemosensors toward F− and OAc− according to the subtle difference in the affinity of F− and OAc−.