Addressing lead toxicity: complexation of lead(II) with thiopyrone and hydroxypyridinethione O,S mixed chelators.
The lead(II) ion is regarded as a serious environmental contaminant. A considerable need exists to develop selective ligands for remediation of this metal ion. Herein, the coordination chemistry of lead(II) is investigated with three O,S donor ligands: thiomaltol, 3-hydroxy-1-methyl-2(1H)-pyridinethione (3,2-HOPTO), and 3-hydroxy-1,2-dimethyl-4(1H)-pyridinethione (3,4-HOPTO). The X-ray structures of [Pb(thiomaltolato)(2)] and [Pb(3,4-HOPTO)(2)] have been solved, revealing the expected 4-coordinate geometries. Electronic spectra have been obtained for the lead(II) complexes with all three ligands. Preliminary solution studies show that the thiomaltol ligand binds lead(II) preferentially over magnesium(II) and calcium(II); however, [Pb(thiomaltolato)(2)] is not stable in the presence of 1 equiv of EDTA. Tetradentate ligands derived from these O,S chelators are expected to generate higher affinity ligands for lead(II) sequestration.
Lewis
Jana A
JA
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, USA.
Cohen
Seth M
SM
D002614:Chelating Agents / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D004563:Electrochemistry / Q000379:methods; D007854:Lead / Q000633:toxicity*; D008024:Ligands; D008968:Molecular Conformation; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry; D011753:Pyrones / Q000138:chemical synthesis* / Q000737:chemistry; D013457:Sulfur Compounds / Q000138:chemical synthesis* / Q000737:chemistry
D002614:Chelating Agents; D008024:Ligands; D009942:Organometallic Compounds; D011725:Pyridines; D011753:Pyrones; D013457:Sulfur Compounds; D007854:Lead