Fluoride Triggered Fluorescence Turn On Sensor for Zn2+ Ions Based on Pentaquinone Scaffold That Works as a Molecular Keypad Lock

A pentaquinone based compound 3a has been synthesized which exhibits pronounced fluorescence enhancement in the presence of Zn2+ ions under a F- triggered synergistic effect. Derivative 3a also behaves as a molecular keypad lock with sequential chemical inputs of Zn2+ and F- ions.