KCS

A novel Schiff base probe, (carbamoyl salicylimine benzothiazole hydrazine) was prepared and measured for its probing ability. High sensitivity was shown for Cu+ and Cu2+. When solvent polarity was regulated by the combination of 100% H2O to 100% acetonitrile, selective sensing of Cu+ or total amount of Cu+ and Cu2+ was possible. In addition, a linear hypsochromic fluorescent shift of about 40 nm was shown. Binding stoichiometry of 1: 1 exists at low concentration. Time-dependent emission measurement showed exponential decay curve (τ1 = 2.99 x 103s, 10 equiv. of Cu+) and linear decay line (slope = -0.02159, 5 equiv of Cu+). Biothiols, L-cysteine, DL-homocysteine, Glutathione reduced, N-acetyl-L-cysteine showed almost complete reversibility of Cu+-induced emission in 50% acetonitrile in H2O, relative to partial reversibility of Cu2+ emission. Herein, by regulation of the ratio between acetonitrile and H2O, Cu+ and Cu+/2+can be probed selectively in this system.