Fluorescent sensing of anions with acridinedione based neutral PET chemosensor

Newly synthesised fluorescent chemosensor ADDTU contains the thiourea receptor connected to the acridinedione (ADD) fluorophore via a covalent bond, giving rise to a fluorophore-receptor motif. In this fluorescent chemosensor, the anion recognition takes place at the receptor site which result in the concomitant changes in the photophysical properties of a ADD fluorophore by modulation of photoinduced electron transfer (PET) process. The binding ability of these sensor with the anions F−, Cl−, Br−, I−, HSO4−, ClO4−, AcO−, H2PO4− and BF4− (as their tetrabutylammounium salts) in acetonitrile were investigated using UV–vis, steady state and time-resolved emission techniques. ADDTU system allows for the selective fluorescent sensing of AcO−, H2PO4− and F− over other anions in acetonitrile.