Toxic metals such as Pb(II), Cd(II), and Hg(II) present a serious environmental concern and have detrimental health effects. Research in our group has pioneered an extraction-based fluorescence and UV-Vis sensing strategy based on selective metal complexation and extraction into an organic phase via an ion-exchange mechanism. Disulfonamide ligands previously synthesized by our group have shown to accomplish selective optical and fluorescence extraction-based sensing of Pb(II), which is ascribed to their unique coordination chemistry with this metal. We have expanded this strategy by investigating the fluorescence and optical effects when altering the central aromatic ring of the ligand framework, such as in 4,5-(NO2)2-1,2-C6H2(NHSO2C6H4-p-tolyl)2, which has been shown to act as an extraction-based Pb(II) optical sensor in the presence of 10-fold and 20-fold higher concentrations of Zn(II) and Ca(II), respectively. Moreover, the complexation properties of additional derivatives including 4,5-(NO2)2-1,2-C6H2(NHSO2C6H4-p-tolyl)2 and 4-NO2-1,2-C6H2(NHSO2C6H4-p-tolyl)2 , with Pb(II) vs. other metals have also been studied structurally and spectroscopically. The phenazine analog 2,3-C6H4N2C6H2(NHSO2C6H4-p-tolyl)2, has been under study for its promising fluorescent sensing properties. These molecules have been isolated in good yields (40-78%) and characterized by spectroscopic techniques such as NMR, IR, UV-Vis and fluorescence. The synthetic methodology and characterization of these compounds will be presented along with their metal complexation studies.

Phenylenediamine and phenazine-derived sulfonamides for fluorescent and optical sensing of toxic metals

251st National Meeting (2016)

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