Fluorene-based chemodosimeter for turn-on sensing of cyanide by hampering ESIPT and live cell imaging

A new salicylaldehyde appended fluorene-based chemodosimeter (FSal) has been designed by taking consideration of the special nucleophilicity of cyanide ion. FSal shows selective affinity towards CN- over other anions (namely F-, Br-, NO3-, ClO4-, N-3(-), H2PO4-, AcO-, I-, Cl-, and NO2-) through turn-on fluorescence with a minimum detection limit of 0.06 ppm. The turn-on fluorescence of the FSal-CN complex resulting from hampering ESIPT is also supported by DFT and TDDFT calculations. Biological compatibility and live cell imaging of this unique probe have also been explored.