Synthesis and X-ray crystal structures of dinuclear hydrogen-bonded cadmium and lead 2-aminoethanethiolates

Bharara, Mohan S.; Kim, Chong H.; Parkin, Sean; Atwood, David A.

doi:10.1016/j.poly.2005.01.019

Cited by 27 publications

(24 citation statements)

References 29 publications

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“…Aminoethanethiolate complexes with metals such as cadmium and mercury have been reported,16 the majority of which form associated structures due to intermolecular interactions between the central metal atom and the sulfur of an adjacent molecule. For example, [Cd(SCH 2 CH 2 NH 2 ) 2 ] 2 consists of dimers arising from μ 2 ‐S bridges, further linked through intermolecular NH ··· S hydrogen bonds 16c. The most direct comparator with 2 is Bi(SCH 2 CH 2 NH 2 ) 3 , where the structure is monomeric but adopts a distorted pentagonal pyramidal structure 17…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Reaction Chemistry of Sb(ECH₂CH₂NMe₂)₃ (E = O, S)

Horley

Kociok‐Köhn

Molloy

et al. 2012

Zeitschrift anorg allge chemie

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The antimony aminoalkoxide and aminothiolates Sb(ECH 2 CH 2 NMe 2 ) 3 [E = O (1), S (2)] were synthesized and their ability to form adducts with other metal moieties investigated. Compound 1 forms 1:1 adducts with NiI 2 (3) and M(acac) 2 [M = Cd (4), Ni (5)], while 2 undergoes ligand exchange with AlMe 3 to afford Me 2-AlSCH 2 CH 2 NMe 2 (6). The structures of 2-4 and 6 were determined. Compound 2 incorporates three S,N-chelating ligands though the inter-1699 action with nitrogen is weaker than in analogous alkoxide complexes. Product 3 reveals one iodine has migrated from nickel to antimony, and all three alkoxide ligands bridge the two metals through μ 2 -O atoms. In contrast, in 4, only one alkoxide links the antimony and cadmium. Compound 6 adopts the same structure, a chelating S,N ligand generating a tetrahedral center at aluminum, as known tBu 2-AlSCH 2 CH 2 NR 2 species (R = Me, Et).

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Section: Resultsmentioning

confidence: 99%

Synthesis and Reaction Chemistry of Sb(ECH₂CH₂NMe₂)₃ (E = O, S)

Horley

Kociok‐Köhn

Molloy

et al. 2012

Zeitschrift anorg allge chemie

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“…The XANES spectra of solutions A2 – G2 were rather similar with only a gradual change in the second derivatives. For solutions A2 – D2 the XANES spectra and their 2 nd derivatives were intermediate to the spectra of Cd(cysteaminate) 2 (as CdS 3 N 2 model) and bis(thiosaccharinato)bis(imidazole) cadmium(II) [Cd(tsac) 2 (Im) 2 ] (as CdS 2 N 2 model) (Figures 5 and S-4) [39, 40]. As the amount of cysteine in solutions E2 – G2 increased to a 10 – 20 fold excess of the ligand, the relative intensity of the two main features in the 2 nd derivative gradually became almost equal.…”

Section: Resultsmentioning

confidence: 99%

“…For solutions A2 – D2 , the Cd L 3 -edge absorption spectra and their 2 nd derivatives are intermediate to the spectra of Cd(cysteaminate) 2 (as CdS 3 N 2 model) and bis(thiosaccharinato)-bis(imidazole) cadmium(II) [Cd(tsac) 2 (Im) 2 ] (as CdS 2 N 2 model) (Figures 4 and S-4) [39, 40]. This is consistent with a mixture of [Cd(Cys) 2 ] 2- and [Cd(Cys) 3 ] 4- complexes in the solutions A2 – D2 .…”

Section: Discussionmentioning

confidence: 99%

“…1). The FEFF input file was generated by means of the ATOMS program [38], using structural information from the crystal structure of the reference compound Cd(SCH 2 CH 2 NH 2 ) 2 (as CdS 3 N 2 model) with both short and long Cd-S, Cd-N(/O) and Cd-Cd distances [39]. Note that two neighboring elements in the periodic table (such as oxygen and nitrogen) obtain very similar amplitude functions f eff ( k ) i and cannot be distinguished by EXAFS.…”

Section: Methodsmentioning

confidence: 99%

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Cadmium(II) Complex Formation with Cysteine and Penicillamine

2009

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The complex formation between cadmium(II) and the ligands cysteine (H2Cys) or penicillamine (H2Pen = 3, 3′-dimethylcysteine) in aqueous solutions, containing CCd(II) ∼ 0.1 mol dm-3 and CH2L = 0.2 – 2 mol dm-3, was studied at pH = 7.5 and 11.0 by means of 113Cd-NMR and Cd K- and L3-edge X-ray absorption spectroscopy. For all cadmium(II)-cysteine mole ratios the mean Cd-S and Cd-(N/O) bond distances were found in the ranges 2.52 – 2.54 Å and 2.27 – 2.35 Å, respectively. The corresponding cadmium(II)-penicillamine complexes showed slightly shorter Cd-S bonds, 2.50 – 2.53 Å, but with the Cd-(N/O) bond distances in a similar wide range, 2.28 – 2.33 Å. For the mole ratio CH2L / CCd(II) = 2, the 113Cd chemical shifts, in the range 509 – 527 ppm at both pH values, indicated complexes with distorted tetrahedral CdS2N(N/O) coordination geometry. With a large excess of cysteine (mole ratios CH2Cys / CCd(II) ≥ 10) complexes with CdS4 coordination geometry dominate, consistent with the 113Cd NMR chemical shifts, δ ∼ 680 ppm at pH 7.5 and 636 - 658 ppm at pH 11.0, and their mean Cd-S distances of 2.53 ± 0.02 Å. At pH 7.5, the complexes are almost exclusively sulfur-coordinated as [Cd(S-cysteinate)4]n-, while at higher pH the deprotonation of the amine groups promotes chelate formation, and at pH 11.0 a minor amount of the [Cd(Cys)3]4- complex with CdS3N coordination is formed. For the corresponding penicillamine solutions with mole ratios CH2Pen / CCd(II) ≥ 10, the 113Cd-NMR chemical shifts, δ ∼ 600 ppm at pH 7.5 and 578 ppm at pH 11.0, together with the average bond distances Cd-S 2.53 ± 0.02 Å and Cd-O 2.30 – 2.33 Å, indicate that [Cd(penicillaminate)3]n- complexes with chelating CdS3(N/O) coordination dominate already at pH 7.5, and become mixed with CdS2N(N/O) complexes at pH 11.0. The present study reveals differences between cysteine and penicillamine as ligands to the cadmium(II) ion that can explain why cysteine-rich metallothionines are capable of capturing cadmium(II) ions, while penicillamine, clinically useful for treating the toxic effects of mercury(II) and lead(II) exposure, is not efficient against cadmium(II) poisoning.

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“…Only in one case both amine and thiolate groups surround the Pb(II) ion (CSD: PAQVOT), with the bond distances Pb-N 2.411 Å and Pb-S 2.704, 2.892 and 3.086 Å (the latter two are bridging). 45 …”

Section: Discussionmentioning

confidence: 99%

Lead(II) Complex Formation with l-Cysteine in Aqueous Solution

et al. 2015

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The lead(II) complexes formed with the multidentate chelator L-cysteine (H2Cys) in alkaline aqueous solution were studied using 207Pb, 13C and 1H NMR, Pb LIII-edge X-ray absorption and UV-vis. spectroscopic techniques, complemented by electro-spray ion mass spectrometry (ESI-MS). The H2Cys/Pb(II) mole ratios were varied from 2.1 to 10.0 for two sets of solutions with CPb(II) = 0.01 and 0.1 M, respectively, prepared at pH values (9.1 – 10.4) for which precipitates of Pb(II)-cysteine dissolved. At low H2Cys/Pb(II) mole ratios (2.1 – 3.0) a mixture of the dithiolate [Pb(S,N-Cys)2]2− and [Pb(S,N,O-Cys)(S-HCys)]− complexes with the average Pb-(N/O) and Pb-S distances 2.42 ± 0.04 Å and 2.64 ± 0.04 Å, respectively, was found to dominate. At high concentration of free cysteinate (> 0.7 M) a significant amount converts to the trithiolate [Pb(S,N-Cys)(S-HCys)2]2−, including a minor amount of a PbS3 coordinated [Pb(S-HCys)3]− complex. The coordination mode was evaluated by fitting linear combinations of EXAFS oscillations to the experimental spectra, and by the 207Pb NMR signals in the chemical shift range δPb = 2006 – 2507 ppm, which became increasingly deshielded with increasing free cysteinate concentration. One-pulse magic angle spinning (MAS) 207Pb NMR spectra of crystalline Pb(aet)2 (Haet = 2-aminoethanethiol or cysteamine) with PbS2N2 coordination were measured for comparison (δiso = 2105 ppm). The UV-vis. spectra displayed absorption maxima at 298 – 300 nm (S− → PbII charge transfer) for the dithiolate PbS2N(N/O) species; with increasing ligand excess a shoulder appeared at ∼ 330 nm for the trithiolate PbS3N and PbS3 (minor) complexes. The results provide spectroscopic fingerprints for structural models for Pb(II) coordination modes to proteins and enzymes.

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Synthesis and X-ray crystal structures of dinuclear hydrogen-bonded cadmium and lead 2-aminoethanethiolates

Cited by 27 publications

References 29 publications

Synthesis and Reaction Chemistry of Sb(ECH₂CH₂NMe₂)₃ (E = O, S)

Synthesis and Reaction Chemistry of Sb(ECH₂CH₂NMe₂)₃ (E = O, S)

Cadmium(II) Complex Formation with Cysteine and Penicillamine

Lead(II) Complex Formation with l-Cysteine in Aqueous Solution

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Synthesis and X-ray crystal structures of dinuclear hydrogen-bonded cadmium and lead 2-aminoethanethiolates

Cited by 27 publications

References 29 publications

Synthesis and Reaction Chemistry of Sb(ECH2CH2NMe2)3 (E = O, S)

Synthesis and Reaction Chemistry of Sb(ECH2CH2NMe2)3 (E = O, S)

Cadmium(II) Complex Formation with Cysteine and Penicillamine

Lead(II) Complex Formation with l-Cysteine in Aqueous Solution

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Synthesis and Reaction Chemistry of Sb(ECH₂CH₂NMe₂)₃ (E = O, S)

Synthesis and Reaction Chemistry of Sb(ECH₂CH₂NMe₂)₃ (E = O, S)