Fluorescence-Based Recognition of Cu(II) Ion in Aqueous Solutions by Ruthenium(II) Complex Linked with Pyridine

A ruthenium-bipyridine based fluorescent chemosensor was employed for the fluorometric and colorimetric Cu(II) detection in 100% aqueous medium. The successive emission quenching of the chemosensor by Cu(II) produced quenching constant (K-SV) of 1.85 x 10(5) M-1. Binding constant (K-b) and the detection limit values for Cu2+ ion by absorption titration were calculated as 9.87 x 10(6) M-1 and 0.6 mu M, respectively. A competitive binding method was used to investigate selectivity toward Cu ion in the presence of other metal ions. Reversibility studies were performed by adding an excess amount of sulfide ion. Reversible cycles and corresponding logic gate were also generated by absorption change. Binding of the chemosensor to Cu2+ occurs in a 1 : 1 stoichiometry using Job's analysis. Cu(II) binding with the chemosensor was established by spectroscopic methods.