A novel cyanide-selective colorimetric and fluorescent chemosensor: First molecular security keypad lock based on phosphotungstic acid and CN− inputs

- Our probe is commercially available with good photo stability and high quantum yield.
- Both color and fluorescence change with long emission wavelength in aqueous media.
- Characteristics of an ON-OFF-ON fluorescence switch.
- The simple receptor for CNˉ detection with low detection limit (≪WHO).
- Mimic the function of a security keypad lock on sequential addition of PTA and CN−.