Characterization of Bis-8-hydroxyquinoline-Armed Diazatrithia-16-crown-5 and Diazadibenzo-18-crown-6 Ligands as Fluorescent Chemosensors for Zinc.

摘要

Bis-8-hydroxyquinoline-armed diazatrithia-16-crown-5 (1) and diazadibenzo-18-crown-6 (2a) ligands selectivity respond to Zn(2+) over other tested metal ions, including Cd(2+), via large increases in fluorescence, while other side-armed diazadibenzo-18-crown-6 ligands (2b-f) and bis(dansylamidoethyl )-armed 1, 8-dimethyltetraza-14-crown-4 ligand (3) do not respond to tested metal ions via an increase in fluorescence. Ligand 1 forms a 1:1 complex (ML) and a 1:2 complex (M2L) with Zn(2+), and these have emission maxima at different wavelengths (540 and 500 nm, respectively). Due to the large fluorescent enhancement factor of ligand 1 for Zn(2+), ligand 1 is well suited for use as a fluorescent chemosensor for Zn(2+).