An AIEE active 1, 8-naphthalimide- sulfamethizole probe for ratiometric fluorescent detection of Hg2+ ions in aqueous media

1,8-Naphthalimide-based sulfamethizole molecule (L6) has been designed and synthesized which have properties like AIEE active, and ratiometric fluorescence sensing of Hg2+ and Ag+ ions. The hydrophobic nature of naphthalimide fluorogenic moiety instigates the aggregation induced emission (AIE) in aqueous medium, led to excimer emission upon intramolecular excimer formation via metal ion-induced assembly. The high selectivity of the sensor was due to quenching of the monomeric emission of L6 at 390 nm with red shift to gradual enhancement in new peak at 483 nm and 478 nm for Hg2+ and Ag+ ions respectively, which is responsible for the ratiometric detection. The competitive experiments revealed that the chemosensor is selective to Hg2+ over Ag+ ion and selective and sensitive ratiometric response to Hg2+ ion without interference of any other metal ions. A limit of detection of Hg2+ ion was found 14.7 nM in 99 % aqueous solution. Also, the visual fluorescence color change of L6 from blue to green was observed under uv-lamp upon addition of Hg2+ ion to L6 solution.