A dual chemosensor for Cu 2+ and Fe 3+ based on π-extend tetrathiafulvalene derivative

A new dual chemosensor ( TTF-PBA ) for Fe 3+ and Cu 2+ in different signal pathways was designed and synthesized. The absorption spectrum, fluorescence spectrum and cyclic voltammograms changed in the presence of Cu 2+ and Fe 3+ . The optical color changed within 5 s from yellow to orange upon the addition of Cu 2+ , and it changed to dark yellow when Fe 3+ existed. The cyclic voltammogram of Cu 2+ /TTF-PBA changed from E ox = 0.50 V, E red = 0.32 V to E ox = 0.64 V, E red = 0.80 V ( vs Ag/AgCl) upon the addition of 2.0 equiv. Cu 2+ . As for Fe 3+ /TTF-PBA, its oxidation wave disappeared, and its reduction wave appeared at E red = −0.59 V ( vs Ag/AgCl) upon the addition of 4.0 equv. Fe 3+ . The sensor displayed high selectivity for Cu 2+ and Fe 3+ over other ions including Pb 2+ , Zn 2+ , Ni 2+ , Ag + , Cr 3+ , Mn 2+ , Al 3+ , Co 2+ , Pd 2+ , Hg 2+ , Fe 2+, Cd 2+ , Ce 3+ , Bi 3+ and Au 3+ , the detection limits for Cu 2+ and Fe 3+ ion reached as low as 5.33 × 10 −7 mol/L and 5.34 × 10 −7 mol/L, respectively. Furthermore, when Fe 3+ existed, Cu 2+ can be detected sequentially by the sensor through the absorption spectrum and the color change observed by naked-eyes.