BODIPY modified 9-cycloheptatrienylidene fluorene derivatives: Fluorescent “turn-on” for detecting Cu2+ with acidity independence

Two fluorescent chemosensors for the detection of Cu2+ were designed, synthesized, and fully characterized. These sensor molecules bear a 9-cycloheptatrienyl fluorene (9-CHF) unit as the Cu2+ receptor and a boron-dipyrromethene (BODIPY) unit as the fluorophore. Both of these two sensors present high selectivity to Cu2+ and high sensitivity with acidity independence. Moreover, they exhibit turn-on fluorescence, which should be more practical in the design of the fluorescent chemosensor for detecting Cu2+.