A Highly Selective Fluorescent Sensor for Pb(2+) Based on a Modified β-Cyclodextrin.

A modified cyclodextrin is synthesized as an anthracene derivative of 6-deoxy- 6-aminoethylamino-β-cyclodextrin and characterized using IR, NMR, and mass spectral techniques. The compound acts as a sensor of Pb(2+) ions in a pool of several metal ions, by enhancement of fluorescence. The absorption spectrum does not show significant changes on the addition of metal ions. The stoichiometry and the binding constant of the complex are determined using fluorescence data. The enhancement of fluorescence is attributed to the aminoethyl and imino nitrogens of the spacer of anthracene and β-cyclodextrin. The compound is quite stable under the testing conditions and the sensing is attributed to the charge transfer mechanism.