A 4-aminophthalimide derive smart molecule for sequential detection of aluminum ions and picric acid

Abstract

A fluorosensor derived from 4-aminophthalimide,((E)-5-((2-hydroxybenzylidene) amino) isoindoline-1, 3-dione, HID) working with excited state intramolecular proton transfer (ESIPT) mechanism is synthesized and employed for the selective recognition of aluminum(Al3+) ions and picric acid (PA) based on ‘off–on-off’ fluorescence mechanism. The sensor HID shows a turn-on fluorescence response towards Al3+ ions in 10 % (v/v) DMSO/H2O with a rapid response time (2 min) and exceptional sensitivity (LOD = 0.56 μM). The binding constant (K) of HID with Al3+ ions is estimated to be 1.32 × 108 M−2. The 1:2 stoichiometries of the complex between HID and Al3+ ions are confirmed through Job’s plot and 1H NMR spectral analysis. Al3+ chelated HID complex is further employed to detect explosive nitroaromatic compounds, especially PA. Furthermore, using these two chemically encoded inputs, viz. Al3+ and PA and corresponding optical output, we have constructed the INHIBIT molecular logic gate. The HID chemosensor and Al3+ chelated HID complex are also applied to map Al3+ ions and PA in the living cell. The HID chemosensor and Al3+ chelated HID complex's performance toward detecting Al3+ ions and PA demonstrates that they might be used as a signaling tool for the analysis of biological and environmental samples.