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

• A novel ‘three-level’ deepened cavitand was synthesized.
• Fe3+ and Cu2+ have good quenching ability to the emission intensity of cavitand.
• The sphere-of-action is the quenching mechanism of both Cu2+ and Fe3+.
• This host could be potentially applied in sensing devices.

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+, Cd2+, Cu2+, Fe3+, Cr3+, Hg2+, La3+, Mn2+, Ni2+, Zn2+ and Co2+, only Fe3+ and Cu2+ 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 Fe3+ and Cu2+ 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+, Mg2+, Ca2+, Co2+, La3+ and Mn2+ do not have significant effects on the determinations of Fe3+ and Cu2+. This cavitand can be potentially applied as optical sensor for the detection of Fe3+ and Cu2+.

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