Ratiometric Sensing of Fluoride Anions Based on a BODIPY-Coumarin Platform

Based on a new coumarin-BODIPY platform, compound 4 was rationally designed and synthesized as a novel ratiometric fluorescent sensor for fluoride anions. The sensor exhibited a large red shift (88 nm) in absorption and a drastic ratiometric fluorescent response (I-472/I-606 = 17.4) to fluoride anions. Density function theory and time-dependent density function theory calculations were conducted to rationalize the optical response of the sensor.