A rigid conjugated pyridinylthiazole derivative and its nanoparticles for divalent copper fluorescent sensing in aqueous media

A rigid conjugated pyridinylthiazole derivative (1) and two bithiazole derivatives with similar structures (2, 3) were synthesized and characterized. Their optical properties were investigated through spectral analysis. By applying the three compounds to Cu2+ ions detection, it was shown that compound 1 could be employed as a selective and sensitive Cu2+ ions fluorescent chemosensor. For aqueous assay, the nanoparticles of compound 1 were prepared in aqueous media. Compared to the monomer, 1 nanoparticles were more fluorescence sensitive to Cu2+ ions. Its binding mode with Cu2+ ions was correlated well with Langmuir equation. Compound 1 nanoparticles exhibit a dynamic working range for Cu2+ ions from 0.02 to 0.50 μM with a detection limit of 10 nM. The proposed chemosensor has been used for the direct measurement of Cu2+ content in drinking water samples with satisfying results.