Spectroscopic properties of a fluorescent pyrene-quinoline-based bisoxime-type sensor and its application to the detection of Cu 2+ion in real water samples

Fluorescent sensors are efficient and convenient tools for metal ions analysis. Herein, a new fluorescent pyrenequinoline-based bisoxime-type sensor PQS , possessing the monomer to excimer emission switching feature, was synthesized and the sensing ability toward Cu 2 + was throughly studied. Interestingly, the blue emission of monomer PQS in dilute solution converted to the green fluorescence of excimer in aggregated state. Meanwhile, the blue fluorescence emission of sensor PQS quenched in the existence of Cu 2 + with no apparent response toward other competitive cations. The plausible complexation ratio 1:1 of sensor PQS to Cu 2 + was substantiated by Job's plot, mass spectrometric analysis combined with the density functional theory calculation. Furthermore, PQS coated paper strips were prepared and used for the rapid and convenient monitoring Cu 2 + in a visible manner.