Fluoride ion-triggered dual fluorescence switch based on naphthalimides winged zinc porphyrin.

A novel fluoride ion-triggered dual fluorescence molecular switch based on naphthalimides winged zinc porphyrin (1) was designed and prepared. The fluorescence of the zinc porphyrin unit could be regulated "ON-OFF" on the excitation of 365 nm and "OFF-ON" on the excitation of 504 nm, respectively, in the presence of fluoride ion. The obvious color changes induced by the intermolecular proton transfer on N-H fragments are clearly visible to the naked eye.