A Carbazole-attached NO2S2-macrocycle exhibiting Hg2+ and Cu2+ selectivity

Abstract

A synthesis and cation-induced fluorescent behavior of the carbazole-attached NO2S2-macrocycle (L) is described and structurally characterized by single crystal X-ray analysis. The photoluminescence spectrum of L in 80% CH3CN/CH2Cl 2 displays a peak maximum at 431 nm (blue emission). In the metal-induced fluorometric experiment, L showed a drastic chelation-enhanced fluorescence quenching (CHEQ) effect only with Hg2+ and Cu 2+. In ESI-mass study, a 1:1 stoichiometry for complexation of L with Hg2+ was confirmed, suggesting the unique sensing behavior of the proposed ligand L due to the selective complexation affinity for Hg 2+. The observed results indicate that L is a promising turn-off type fluoroionophore for Hg2+ and Cu2+ detections. Additionally, the Ag+ complex of the precursor macrocycle was prepared and its solid structure was crystallographically characterized.