Dual-Channel More Flexible Salamo-Like Chemosensor for Fluorogenic Sensing of Copper Ion in Semi-Aqueous Medium

The optical properties of the symmetric salamo-like chemical probe (H2CS) of Cu2+ were studied in EtOH/H2O (1:1, v/v) solution by UV-Vis and fluorescence spectroscopy. In the fluorescence spectrum, the coordination of Cu2+ with H2CS results in fluorescence quenching owing to the paramagnetic nature of Cu2+ ions. The binding constant of Cu2+ to the H2CS sensor was calculated as 1.17 x 10(11) M-1 and LOD was obtained as 5.3 x 10(-8) M. When Cu2+ ions were added, the UV-Vis spectra changed, obviously due to the electron transfer from sensor to metal bond, and a new absorption band appeared at 372 nm. When the ethylenediaminetetraacetic acid (EDTA) solution was added to the H2CS-Cu2+ solution, causing a large binding constant, with EDTA releasing the free sensor molecule and finally achieving a fluorescence shutdown phenomenon.

Automated summary

The optical properties of the symmetric salamo-like chemical probe (H2CS) of Cu2+ were investigated and fluorescence quenching was observed. The binding constant and LOD of Cu2+ to the H2CS sensor were calculated, and significant changes in the UV-Vis spectra were observed when Cu2+ ions were added. The fluorescence shutdown phenomenon was achieved by adding EDTA to the H2CS-Cu2+ solution.