Chalcone-based fluorescent chemosensors as new tools for detecting Cu2+ ions

The design and full characterization of new fluorescent chemosensors for Cu2+ is herein presented. The structure of the sensors is based on a chalcone backbone as the chromophoric unit, with di-(2-picolyl)amine (DPA) as a receptor moiety. Two systems, bearing one or two chalcone-DPA units, were synthesized and fully characterized. UV-Vis titrations with several metal ions were performed and both chemosensors exhibited a strong hypsochromic shift in the absorption spectra upon Cu2+ addition, indicating a higher selectivity for this metal over other divalent cations. Additionally, fluorescent spectra recorded in the same conditions revealed a stronger quenching effect in the presence of Cu2+, even in the presence of other metal cations, with association constants above 106 M-1 and detection limits below the micromolar level for both chemosensors. Paper test-strips with one of the chemosensors were prepared to attest its possible application for detecting copper in aqueous samples.

Automated summary

The study presents the design and characterization of new fluorescent chemosensors for Cu2+, showing high selectivity for copper ions and low detection limits. The results suggest potential applications of these sensors for detecting copper in aqueous samples.