A novel naphthalimide-based supramolecular gel for sensing of Fe3+ in aqueous medium and its application

In view of our research interests in stimuli-responsive supramolecular functional materials and ion recognition, a novel organogelator based on naphthalimide (NA) was successfully synthesized via a 3-step pathway. The obtained gelator NA could serve as a supramolecular π-gel(ONA) in 1,2-Propanediol by a series of self-assembly driving forces, which showed bright blue aggregation-induced emission (AIE). Interestingly, the organogel ONA showed a fluorescence “turn-off” for Fe3+ in the gel-gel state. Furthermore, the Fe3+ coordinated organogel Fe-ONA could detect H2PO4−successively in fluorescence spectrum. The fluorescence responding circles ‘‘on–off–on’’ could be performed 4 times when alternating the addition of Fe3+ and H2PO4− to ONA. The bonding mechanisms between supramolecular organogel (ONA) and ions were detected by a series of characterization. Even more significantly, the supramolecular gel ONA can be used to adsorb Fe3+ from aqueous media and the adsorption percentage of ONA xerogel for Fe3+ ions can reach up to 92.26%.