A dual target chemosensor for the fluorometric detection of In 3+ and colorimetric detection of Fe 3 .

A new dual target chemosensor 1, 1,1′‑((1E,1′E)‑((thiobis(ethane‑2,1‑diyl))bis(azanylylidene))bis(methanylylidene))bis(naphthalen‑2‑ol), was prepared by the reaction of a hydroxy-naphthaldehyde and a thiobis(ethylamine). Sensor 1 detected In3+ with turn-on fluorescence and Fe3+ via the change of color from colorless to pale violet. The sensing behaviors of 1 toward In3+ and Fe3+ were studied through photophysical experiments, ESI-mass, NMR titration, and theoretical calculations. In particular, 1 can discriminate In3+ from Al3+ and Fe3+ from Fe2+. Limits of detection for the analysis of In3+ and Fe3+ ions turned out to be 5.89 μM and 0.30 μM, respectively. In addition, sensor 1 functioned practically as a naked-eye test strip for Fe3+ and could be recycled by using EDTA for In3+ and DFO for Fe3+.