Solid‐state <sup>207</sup>Pb NMR studies of lead‐group 16 and mixed transition‐metal/lead‐group 16 element‐containing materials

Bramer, Scott E. Van; Glatfelter, Alicia; Bai, Shi; Dybowski, Cecil; Neue, G.; Perry, Dale L.

doi:10.1002/mrc.1751

Cited by 16 publications

(20 citation statements)

References 34 publications

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“…Ligands containing S, N, or O donor atoms generally shield the 207 Pb nucleus in the order S < N < O. 52, 59–62 Table 2 summarizes reported 207 Pb chemical shifts for Pb(II) complexes with sulfur-containing ligands.…”

Section: Resultsmentioning

confidence: 99%

Similarities between N-Acetylcysteine and Glutathione in Binding to Lead(II) Ions

Sisombath

Jalilehvand

2015

Chem. Res. Toxicol.

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N -acetylcysteine is a natural thiol-containing antioxidant, a precursor for cysteine and glutathione, and a potential detoxifying agent for heavy metal ions. However, previous accounts of the efficiency of N-acetylcysteine (H2NAC) in excretion of lead are few and contradicting. Here we report results on the nature of lead(II) complexes formed with N-acetylcysteine in aqueous solution, which were obtained by combining information from several spectroscopic methods, including 207Pb, 13C and 1H NMR, Pb LIII-edge X-ray absorption, Ultraviolet-visible (UV-vis.) spectroscopy and electro-spray ionization mass spectrometry (ESI-MS). Two series of solutions were used containing CPb(II) = 10 and 100 mM, respectively, varying the H2NAC / Pb(II) mole ratios from 2.1 to 10.0 at pH = 9.1 – 9.4. The coordination environments obtained resemble those previously found for the Pb(II) glutathione system: at a ligand-to-lead mole ratio of 2.1 dimeric or oligomeric Pb(II) N-acetylcysteine complexes are formed, while a tri-thiolate [Pb(NAC)3]4− complex dominates in solutions with H2NAC/Pb(II) mole ratios > 3.0.

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Section: Resultsmentioning

confidence: 99%

Similarities between N-Acetylcysteine and Glutathione in Binding to Lead(II) Ions

Sisombath

Jalilehvand

2015

Chem. Res. Toxicol.

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“…207 Pb is an attractive nucleus for NMR studies: it has a natural abundance of 22.1%, I = 1 / 2 nuclear spin and a receptivity of 11.7, relative to 13 C. Its chemical shift spans over a wide range (∼17 000 ppm) and is sensitive to changes in the local structure, coordination number, and electronic environment around the 207 Pb nucleus, concentration, and temperature. 35 , 36 , 46 − 48 The nature of the bonding (covalent versus ionic) between the Pb(II) ion and the donor atom of the ligand and its polarizability influences the shielding around the Pb nucleus; for biologically relevant donor atoms the shielding increases in the order S < N < O. 35 , 46 , 49 …”

Section: Resultsmentioning

confidence: 99%

Lead(II) Binding to the Chelating Agent d-Penicillamine in Aqueous Solution

et al. 2014

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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) mole ratio (2.0, 3.0, 4.0, 10.0). 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 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.

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“…[16][17][18][19] Recently, we have focused on spinlattice relaxation of 207 Pb and 111,113 Cd in ionic solids 4,5,14,15 and have begun projects for 119 Sn and 199 Hg. The study of heavy-nucleus spin-lattice relaxation is a field in its infancy.…”

Section: Introductionmentioning

confidence: 99%

“…Spin-rotation relaxation in solids akin to the process prevailing in gases has been observed in only very few cases involving nearly unobstructed rotation of structural units. Examples are spin-lattice relaxation of 19 F in SF 6 , SeF 6 , and TeF 6 ͑Ref. 24͒ and of 13 C in C 60 .…”

Section: Introductionmentioning

confidence: 99%

Spin-lattice relaxation of heavy spin-1/2 nuclei in diamagnetic solids: A Raman process mediated by spin-rotation interaction

et al. 2006

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We present a theory for the nuclear spin-lattice relaxation of heavy spin-1/2 nuclei in solids, which explains within an order of magnitude the unexpectedly effective lead and thallium nuclear spin-lattice relaxation rates observed in the ionic solids lead molybdate, lead chloride, lead nitrate, thallium nitrate, thallium nitrite, and thallium perchlorate. The observed rates are proportional to the square of the temperature and are independent of magnetic field. This rules out all known mechanisms usually employed to model nuclear spin relaxation in lighter spin-1/2 nuclei. The relaxation is caused by a Raman process involving the interactions between nuclear spins and lattice vibrations via a fluctuating spin-rotation magnetic field. The model places an emphasis on the time dependence of the angular velocity of pairs of adjacent atoms rather than on their angular momentum. Thus the spin-rotation interaction is characterized not in the traditional manner by a spin-rotation constant but by a related physical parameter, the magnetorotation constant, which relates the local magnetic field generated by spin rotation to an angular velocity. Our semiclassical relaxation model involves a frequency-mode description of the spectral density that can directly be related to the mean-square amplitudes and mode densities of lattice vibrations in the Debye model.

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Solid‐state ²⁰⁷Pb NMR studies of lead‐group 16 and mixed transition‐metal/lead‐group 16 element‐containing materials

Cited by 16 publications

References 34 publications

Similarities between N-Acetylcysteine and Glutathione in Binding to Lead(II) Ions

Similarities between N-Acetylcysteine and Glutathione in Binding to Lead(II) Ions

Lead(II) Binding to the Chelating Agent d-Penicillamine in Aqueous Solution

Spin-lattice relaxation of heavy spin-1/2 nuclei in diamagnetic solids: A Raman process mediated by spin-rotation interaction

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Solid‐state 207Pb NMR studies of lead‐group 16 and mixed transition‐metal/lead‐group 16 element‐containing materials

Cited by 16 publications

References 34 publications

Similarities between N-Acetylcysteine and Glutathione in Binding to Lead(II) Ions

Similarities between N-Acetylcysteine and Glutathione in Binding to Lead(II) Ions

Lead(II) Binding to the Chelating Agent d-Penicillamine in Aqueous Solution

Spin-lattice relaxation of heavy spin-1/2 nuclei in diamagnetic solids: A Raman process mediated by spin-rotation interaction

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Solid‐state ²⁰⁷Pb NMR studies of lead‐group 16 and mixed transition‐metal/lead‐group 16 element‐containing materials