Abstract

SYNTHESIS, LUMINESCENCE, AND ELECTROCHEMICAL STUDIES OF DIOXADIAZA- MACROCYCLE AND EXTRACTION OF TOXIC METALS

Lynda Merlin D.*

Abstract

The synthesis and photophysical and electrochemical properties of dioxadiaza macrocycle are reported. The 16-membered dioxadiaza macrocycle, 5,6,14,15-dibenzo-1,4-dioxa-8,12-diazacyclopentadeca- 5,14-diene (L1) is synthesized by the Schiff base condensation of 1,4- bis(2′-formylphenyl)-1,4-dioxabutane (1) with 1,3-diaminopropane in dry ethanol followed by the in situ reduction of the Schiff base macrocycles using sodium borohydride and borax and characterized by single-crystal X-ray diffraction: triclinic, P-1. The free ligands L1 emit in the visible region at 691 nm upon excitation in the UV region at 262 nm. The complexation of these macrocycles with these toxic metal ions is robust and leads to a large shift in emission maxima depending on the nature of the metal ion. The efficient complexation of these metal ions by the macrocycle L1 could be exploited for the removal of these metal ions from the environmental samples. The ligand systems L1 could serve as potential photochemical chemosensors for Cd(II), Hg(II), and Pb(II) as they are able to bind with these metal ions, and at the same time, signal their presence in fluid solution by the chelation enhanced fluorescence effect.

Keywords: Macrocycles, Toxic metals, Heavy metals.