A novel imidazophenazine-based metallogel act as reversible H2PO4− sensor and rewritable fluorescent display material

- Novel 1H-imidazo[4,5-b]phenazine-based organogelator and sensor.
- Metallogel-based reversible H2PO4− sensor could act as H2PO4− test kits.
- 1H-imidazo[4,5-b]phenazine moiety acts as signal group and binding sites.
- High selectivity and sensitivity for H2PO4−.
- Metallogel-based rewritable security display materials.

By rationally introduced 1H-imidazo[4,5-b]phenazine moiety into the gelator molecular, a novel organogelator G5 was designed and synthesized. Imidazophenazine moiety could act as fluorescent group as well as binding site. The gelator G5 could form a stable organogel (OG5) accompanied with dramatic aggregation-induced emission enhancement (AIEE) in DMF. The AIEE of OG5 could be quenched by adding Fe3+ into the OG5. Meanwhile, OG5 could form no fluorescence stable metallogel (FeG) with Fe3+. Interestingly, the metallogel (FeG) could reversibly fluorescent “turn-on” sense H2PO4− with high selectivity and sensitivity. The detection limit of FeG for H2PO4− is 1.0 × 10−6 mol L−1, moreover, other ions did not interfere in the sensing process. The H2PO4− sensing mechanism was confirmed based on competitive coordination between gelator, Fe3+ and H2PO4−. The metallogel FeG could act as reversible H2PO4− sensor and convenient H2PO4− test kits. In addition, the FeG film also could act as an rewritable fluorescent display material.

By rationally introduced imidazophenazine group into the gelator molecular as fluorescent and binding sites, a novel supramolecular metallogel-based H2PO4− response material has been developed. The supramolecular metallogel could sense H2PO4− with high selectivity and sensitivity in aqueous solution. This metallogel can act as an 'Off-On-Off' fluorimetric sensor and a rewritable fluorescent display material.128