Fluorescence quenching studies on the interaction of a novel deepened cavitand towards some transition metal ions

A novel 'three-level' deepened cavitand featuring a significantly sizable portal has been synthesized and its interaction with some transition metal ions has been investigated in THF/H2O binary solvent using fluorescence quenching technique. The results suggest that among the used transition metal ions including Ag(+), Cd(2+), Cu(2+), Fe(3+), Cr(3+), Hg(2+), La(3+), Mn(2+), Ni(2+), Zn(2+) and Co(2+), only Fe(3+) and Cu(2+) show good quenching ability. In order to interpret the quenching mechanism, the Stern-Volmer kinetics, and the presence of both the dynamic and static quenching have been discussed. It was found that the simultaneous presence of the sphere-of-action static quenching and dynamic quenching model agrees very well with the experimental results. The limits of detection for Fe(3+) and Cu(2+) were found to be 2.1×10(-6) mol L(-1) (3σ) and 3.6×10(-6) mol L(-1) (3σ), respectively. Cations with potential interference, such as K(+), Na(+), Mg(2+), Ca(2+), Co(2+), La(3+) and Mn(2+) do not have significant effects on the determinations of Fe(3+) and Cu(2+). This cavitand can be potentially applied as optical sensor for the detection of Fe(3+) and Cu(2+).