Selective colorimetric and ratiometric signaling of Cu2+ ions by thiosemicarbazone-appended 3-hydroxynaphthalimide

- A new thiosemicarbazone appended 3-hydroxynaphthalimide 1 was prepared.
- Sensor 1 showed pronounced Cu2+ selectivity in the presence of metal ions and anions.
- Interference from Hg2+ ions was suppressed by using iodide ions as a masking agent.
- Practical application for signaling of Cu2+ in wastewater by extraction was possible.