Pyrene pyridine-conjugate as Ag selective fluorescent chemosensor

A new pyrene pyridine conjugate ( PPC ) has been developed as a selective fluorescent sensor for Ag + ion. Probe PPC exhibits high selectivity and sensitivity toward Ag + as fluorescence ‘on–off’ behaviour in HEPES-buffered DMSO–H 2 O (1 : 1, (v/v) HEPES = 50 mM, pH = 7.4) solution with a detection limit of 0.29 × 10 −8 M −1 . The turn-off fluorescence sensing of the Ag + ion occurs through dual pathways, i.e. changes and alternations in the photophysical properties. The binding of Ag + ion prevents excimer formation and also induces intramolecular photoinduced electron transfer (PET) from the pyridine–Ag + ion bound receptor to pyrene because of structural rigidification, which quenches excimer and monomer emissions with a butterfly-like skeleton.