A simple pyridine based fluorescent chemosensor for selective detection of copper ion

A feasibly constructed novel pyridine based receptor (S) has been reported for the selective detection of copper ion over other metal ions. The metal sensing ability of receptor with diverse metal ions were studied by colorimetry, absorption and emission spectroscopic systems in CH₃CN/H₂O (7:3, v/v). This receptor reveals a drastic color converts from vapid to yellow and cyan under normal light and UV light with copper ion. Further, S-Cu²⁺ complex exhibits new UV-Visible band at 419 nm and intense fluorescence band at 494 nm upon the excitation at 388 nm. The stoichiometric binding ratio of receptor with metal ion was confirmed with Job's method and ESI-Mass also further supported the complexation. Besides, limits of detection of Cu²⁺ were calculated to be 0.25 μM. The limiting capacity of receptor with Cu²⁺ ion was additionally explored by quantum chemical calculation. Moreover, this receptor was effectively utilized for the measurement of Cu²⁺ ion in various water tests.