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.
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, USA.
Jana A
JA
Lewis
Seth M
SM
Cohen
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