A highly selective and ratiometric molecular probe for cyanide sensing based on a phenothiazine-hemicyanine dye

A new ratiometric fluorescent probe was designed based on hemicyanine moiety as a cyanide reaction site for nucleophilic addition. The titration experiment for CN-showed this probe exhibits high selectivity, a low limit of detection to 20 nM and quick response for CN-sensing. At the addition of CN-, the colour of the solution changed from purple to colourless, accompanied by an increase in the fluorescence intensity. The sensing behavior was investigated by changes of UV-vis spectra, HRMS and H-1 NMR. Furthermore a HepG2 cell imaging experiment demonstrated the application prospect for tracing cyanide anions in biological systems.