Acylhydrazone functionalized naphthalene-based self-assembled supramolecular gels for efficient fluorescence detection of Fe.

A new gel factor (named N) has been successfully designed and synthesized, which contains the conventional fluorophore naphthalene with the acylhydrazone bond as the self-assembly site. It can be self-assembled into stable organogels (named ON) in dimethyl sulfoxide (DMSO) and water mixed medium ( :  = 4 : 1) with a critical gel temperature and concentration (55 °C and 10 mg mL). Interestingly, under 365 nm UV light, the ON exhibits bright yellow Aggregation Induced Emission (AIE). The supramolecular organogel ON shows a fluorescent "OFF" response to the metal ions Fe, and the state of the gel ON remains constant before and after detection. Notably, the minimum detection limits (LODs) of the gel ON for Fe are as low as 1.30 × 10 M. The binding mechanism of supramolecular organogels (ON) to ions has been investigated through a series of characterizations. Meanwhile, the organogel sensor ON can also be used as an ion-responsive membrane for the detection of Fe in the aqueous phase.