1,8-Naphthalimide derivative-based turn-off fluorescent probe for the detection of picrate in organic aqueous media

Abstract

The synthesis of a simple fluorescent naphthalimide- based receptor N-allyl-4-iminodi(N-butylacetamide)- 1,8-naphthalimide 3 was carried out as a selective picrate (Pic-) anion probe, and the detecting behavior of this probe was studied by fluorescence spectroscopy. In DMF solution, the interaction of compound 3 with different anions, including Pic-, F-, Cl-, Br-, I-, OH-, Ac-, NO3-, ClO4-, SCN-, SO32-, SO42-, H2PO4-, and HPO42-, revealed significant fluorescence quenching only with the Pic- Anion. By adding the picrate anions, green-yellow fluorescence emission quenches, which is easily observed by naked eyes under a 365 nm UV light irradiation. This phenomenon is essential for producing a highly selective and sensitive fluorescent probe for picrate anions. The probe can be applied to the quantification of Pic- with a linear range covering from 4.97 ×10-6 to 6.82 ×10-5m and a detection limit of 5.8 ×10-7 m. Most importantly, probe 3 has a high selectivity for picrate over competitive anions and picrate-containing analytes, which meet the selective requirements for practical application. Thus, the present results would be inspiring findings in the future design of reaction-based fluorescent turn-off probes for the environmentally relevant picrate probe.