1353-1361Naphthalimide based receptor 1 with N-substituted benzothiazole and pyrrolidine subunit is designed, synthesized, and
characterized using FT-IR,1H and 13C NMR spectroscopy and mass spectrometry techniques. The receptor 1 exhibits
prominent optical response for Hg2+and Pb2+ions allowing the detection of these ions in acetonitrile (ACN). The formation
of the receptor 1:cation complexes have been investigated using UV-Vis and fluorescence emission titration. Further, the
selectivity of the receptor 1towards Hg2+and Pb2+ ions on the presence of various interfering cations such as Mg2+, Ba2+,
Ni2+, Co2+, Cu2+, Ag2+, Fe2+, Fe3+and Cr3+ has been confirmed by UV-Vis and fluorescence spectroscopy. The binding
constant between receptor 1 and Hg2+ and Pb2+ was estimated by Benesi-Hildebrand plot and equations. The binding
constants have been found to be Ka= 3.43286 10−6 and Ka= 2.84079 10−6 M for Hg2+ and Pb2+, respectively. The limit of
detection (LOD) for Hg2+and Pb2+by receptor 1are down to 7.44 10−10 M and 1.26 10−9 M, respectively. In addition,
Job’s plot analysis reveals 1:2 binding stoichiometry between the receptor 1 and Pb2+ and Hg2+ cations