CHED 1195 |
| Ion-exchange extraction of toxic metals using ionizable sulfonamides have shown promise for selective separation and sensing applications. Our group has previously presented o-phenylenediamine-derived sulfonamides that can efficiently extract Pb(II) from water into 1,2-dichloroethane, when used together with a 2,2'-bipy coligand (bipy). However it has also been shown that the bipy, which was used in order to increase complex solubility, reduces selectivity for extraction of Pb(II) against Cu(II) and Zn(II). We are now reporting an analogous chelating ligand N,N'-di-(3,4-dimethoxyphenyl)-1,2-benzenedisulfonamide that can extract Pb(II) into 1,2-dichloroethane (DCE), efficiently and selectively, without the need of a bipy coligand. The Pb(II)-sulfonamido binary complex, the ternary Cd(II)-sulfonamido-NH(i-Pr)2 complex, and the analogous ternary complexes with bipy were also isolated and characterized showing coordination with one bipy ligand for Pb(II) and two bipy ligands for Cd(II). Distribution experiments and measurement of metal concentrations in the aqueous samples by ICP-MS showed that extraction of Pb(II) is selective over both Cd(II) and Zn(II), in the absence of bipy. Further structural and spectroscopic investigations provide insight of the ligand effects to Pb(II) extraction selectivity. |
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Undergraduate Research Poster Session: Inorganic Chemistry
2:00 PM-4:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Chemical Education |