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Title: Lead(II) binding to the chelating agent d-penicillamine in aqueous solution

Here, a spectroscopic investigation of the complexes formed between the Pb(II) ion and d-penicillamine (H 2Pen), a chelating agent used in the treatment of lead poisoning, was carried out on two sets of alkaline aqueous solutions with C Pb(II) ≈ 10 and 100 mM, varying the H 2Pen/Pb(II) molar ratio (2.0, 3.0, 4.0, 10.0). Ultraviolet–visible (UV-vis) spectra of the 10 mM Pb(II) solutions consistently showed an absorption peak at 298 nm for S → Pb(II) ligand-to-metal charge-transfer. The downfield 13C NMR chemical shift for the penicillamine COO group confirmed Pb(II) coordination. The 207Pb NMR chemical shifts were confined to a narrow range between 1806 ppm and 1873 ppm for all Pb(II)-penicillamine solutions, indicating only small variations in the speciation, even in large penicillamine excess. Those chemical shifts are considerably deshielded, relative to the solid-state 207Pb NMR isotropic chemical shift of 909 ppm obtained for crystalline penicillaminatolead(II) with Pb(S,N,O-Pen) coordination. The Pb L III-edge extended X-ray absorption fine structure (EXAFS) spectra obtained for these solutions were well-modeled with two Pb–S and two Pb-(N/O) bonds with mean distances 2.64 ± 0.04 Å and 2.45 ± 0.04 Å, respectively. The combined spectroscopic results, reporting δ( 207Pb) ≈ 1870 ppm and λmore » max ≈ 298 nm for a Pb IIS 2NO site, are consistent with a dominating 1:2 lead(II):penicillamine complex with [Pb(S,N,O-Pen)(S-H nPen)] 2–n (n = 0–1) coordination in alkaline solutions, and provide useful structural information on how penicillamine can function as an antidote against lead toxicity in vivo.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1]
  1. Univ. of Calgary, Calgary, AB (Canada)
Publication Date:
Grant/Contract Number:
AC02-76SF00515
Type:
Accepted Manuscript
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 53; Journal Issue: 23; Journal ID: ISSN 0020-1669
Publisher:
American Chemical Society (ACS)
Research Org:
Univ. of Calgary, Calgary, AB (Canada)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1345619

Sisombath, Natalie S., Jalilehvand, Farideh, Schell, Adam C., and Wu, Qiao. Lead(II) binding to the chelating agent d-penicillamine in aqueous solution. United States: N. p., Web. doi:10.1021/ic5018714.
Sisombath, Natalie S., Jalilehvand, Farideh, Schell, Adam C., & Wu, Qiao. Lead(II) binding to the chelating agent d-penicillamine in aqueous solution. United States. doi:10.1021/ic5018714.
Sisombath, Natalie S., Jalilehvand, Farideh, Schell, Adam C., and Wu, Qiao. 2014. "Lead(II) binding to the chelating agent d-penicillamine in aqueous solution". United States. doi:10.1021/ic5018714. https://www.osti.gov/servlets/purl/1345619.
@article{osti_1345619,
title = {Lead(II) binding to the chelating agent d-penicillamine in aqueous solution},
author = {Sisombath, Natalie S. and Jalilehvand, Farideh and Schell, Adam C. and Wu, Qiao},
abstractNote = {Here, a spectroscopic investigation of the complexes formed between the Pb(II) ion and d-penicillamine (H2Pen), a chelating agent used in the treatment of lead poisoning, was carried out on two sets of alkaline aqueous solutions with CPb(II) ≈ 10 and 100 mM, varying the H2Pen/Pb(II) molar ratio (2.0, 3.0, 4.0, 10.0). Ultraviolet–visible (UV-vis) spectra of the 10 mM Pb(II) solutions consistently showed an absorption peak at 298 nm for S– → Pb(II) ligand-to-metal charge-transfer. The downfield 13C NMR chemical shift for the penicillamine COO– group confirmed Pb(II) coordination. The 207Pb NMR chemical shifts were confined to a narrow range between 1806 ppm and 1873 ppm for all Pb(II)-penicillamine solutions, indicating only small variations in the speciation, even in large penicillamine excess. Those chemical shifts are considerably deshielded, relative to the solid-state 207Pb NMR isotropic chemical shift of 909 ppm obtained for crystalline penicillaminatolead(II) with Pb(S,N,O-Pen) coordination. The Pb LIII-edge extended X-ray absorption fine structure (EXAFS) spectra obtained for these solutions were well-modeled with two Pb–S and two Pb-(N/O) bonds with mean distances 2.64 ± 0.04 Å and 2.45 ± 0.04 Å, respectively. The combined spectroscopic results, reporting δ(207Pb) ≈ 1870 ppm and λmax ≈ 298 nm for a PbIIS2NO site, are consistent with a dominating 1:2 lead(II):penicillamine complex with [Pb(S,N,O-Pen)(S-HnPen)]2–n (n = 0–1) coordination in alkaline solutions, and provide useful structural information on how penicillamine can function as an antidote against lead toxicity in vivo.},
doi = {10.1021/ic5018714},
journal = {Inorganic Chemistry},
number = 23,
volume = 53,
place = {United States},
year = {2014},
month = {11}
}