Nuclear magnetic resonance studies of the solution chemistry of metal complexes. 20. Ligand-exchange kinetics of methylmercury(II)-thiol complexes

Rabenstein, Dallas L.; Reid, R. S.

doi:10.1021/ic00177a016

Cited by 54 publications

(38 citation statements)

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“…The model complexes with monomeric amino acids considered so far involved mainly the sulfurcontaining acids (8)(9)(10)(11)(12)(13). Selenium analogs have also been examined (14).…”

Section: Introductionmentioning

confidence: 99%

Complexation of glycylglycine by the methylmercury cation: a vibrational spectroscopy and X-ray diffraction study

Alex¹,

Savoie²,

Corbeil³

et al. 1986

Can. J. Chem.

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“…The model complexes with monomeric amino acids considered so far involved mainly the sulfurcontaining acids (8)(9)(10)(11)(12)(13). Selenium analogs have also been examined (14).…”

Section: Introductionmentioning

confidence: 99%

Complexation of glycylglycine by the methylmercury cation: a vibrational spectroscopy and X-ray diffraction study

Alex¹,

Savoie²,

Corbeil³

et al. 1986

Can. J. Chem.

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“…This was first demonstrated by nuclear magnetic resonance (NMR) studies (Rabenstein et al, 1982;Rabenstein and Reid, 1984;Cheesman et al, 1988). The ligand exchange occurs via an associative mechanism involving a three-coordinated Hg intermediate (Rabenstein and Reid, 1984;Cheesman et al, 1988): where RS(e) − and R S(e) − refer to two identical (when R = R ) or different thiols or selenols. The equilibrium composition favors the complex with a higher formation constant (Rabenstein and Reid, 1984).…”

Section: Lability Of Mercury or Methylmercury Complexes With Thiols Omentioning

confidence: 88%

“…The ligand exchange occurs via an associative mechanism involving a three-coordinated Hg intermediate (Rabenstein and Reid, 1984;Cheesman et al, 1988): where RS(e) − and R S(e) − refer to two identical (when R = R ) or different thiols or selenols. The equilibrium composition favors the complex with a higher formation constant (Rabenstein and Reid, 1984). The recent development of a new high performance liquid chromatographyinductively coupled plasma-mass spectrometry (HPLC-ICP-MS) analytical technique (Lemes and Wang, 2009) allows us to directly examine such ligand exchange in aqueous solutions.…”

Section: Lability Of Mercury or Methylmercury Complexes With Thiols Omentioning

confidence: 99%

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Metallomics of Mercury: Role of Thiol‐ and Selenol‐Containing Biomolecules

Wang¹,

Lemes²,

Khan³

2011

Environmental Chemistry and Toxicology of Mercury

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“…The main targets for this type of complexation are thiol ligands (2)(3)(4)(5), such as the cysteine residues in proteins, although other sites are also involved. Complex formation through the sulfur atom is easily characterized by vibrational spectroscopy (4)(5)(6)(7)(8)(9) and the substitution of a proton of an amino group by a methylmercury(I1) cation also gives specific vibrational bands (10)(11)(12)(13).…”

Section: Introductionmentioning

confidence: 99%

A Raman spectroscopic study of the complexation of the methylmercury(II) cation by amino acids

Alex¹,

Savoie²

1987

Can. J. Chem.

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. Can. J. Chem. 65,491 (1987). A systematic Raman spectroscopic investigation of the complexation of CH3Hg+ by the standard amino acids is reported. It is shown that the vibrational bands due to the ligand-Hg and Hg-CH3 stretching modes and to the symmetric -CH3 bending mode of the -HgCH3 unit are well suited to characterize the extent of complexation and the sites of attachment of the cation. Coordination, which occurs mostly on sulfur and nitrogen atoms by substitution of a proton on the thiol group of cysteine or on amino groups in general, is best identified by the frequency of the ligand-Hg stretching vibration in the 250-550 cm-' region of the spectrum. SERGE ALEX et RODRIGUE SAVOIE. Can. J. Chem. 65,49 1 (1987). La complexation de l'ion CH3Hg+ par les acides aminCs usuels a t t t CtudiCe systCmatiquement par spectroscopie Raman. On dCmontre que les bandes dues aux vibrations de valence des ensembles ligand-Hg et Hg-CH3, de m&me que celle attribuable au mode de dkformation symCtrique du groupe CH3, rCflktent bien le degrC de complexation et le site de fixation du cation.La coordination, qui implique principalement les atomes de soufre et d'azote suite i une substitution d'un proton sur le groupe thiol de la cystkine ou sur les groupes amines en gCnCral, est la mieux identifiCe par la frCquence du mode de vibration de valence ligand-Hg dans la rCgion de 250 i 550 cm-' du spectre. IntroductionThe mercury (~g~+ ) and methylmercury (CH3Hg+) cations are known to react extensively with living organisms (1). The main targets for this type of complexation are thiol ligands (2-5), such as the cysteine residues in proteins, although other sites are also involved. Complex formation through the sulfur atom is easily characterized by vibrational spectroscopy (4-9) and the substitution of a proton of an amino group by a methylmercury(I1) cation also gives specific vibrational bands (10-13). We have recently studied in detail several complexes of methylmercury with some amino acids (alanine and glycine) (lo), a dipeptide (glycylglycine) (1 l), and a small polypeptide (glutathione) (14). These studies have shown that the formation of S-Hg and N-Hg bonds by substitution of a proton on a -SH or -NH3+ group readily occurs in these systems. These complexation processes were followed by monitoring the frequencies and intensities of the v(Hg-ligand), v(Hg-CH,), and 6(CH3) bands (v = stretching and 6 = bending), which are particularly intense in the Raman spectra.It became obvious in the above studies that the ~otential of Raman spectroscopy for determining the possible sites of complexation of the CH3Hg+ ion by amino acids and proteins in general had not been used to its full capacity. Also lacking in certain cases was an accurate knowledge of the conditions under which complexation could occur. The present paper gives an account of a systematic Raman spectroscopic investigation of this problem, -using standard amino acids and small parent molecules.

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Nuclear magnetic resonance studies of the solution chemistry of metal complexes. 20. Ligand-exchange kinetics of methylmercury(II)-thiol complexes

Cited by 54 publications

References 0 publications

Complexation of glycylglycine by the methylmercury cation: a vibrational spectroscopy and X-ray diffraction study

Complexation of glycylglycine by the methylmercury cation: a vibrational spectroscopy and X-ray diffraction study

Metallomics of Mercury: Role of Thiol‐ and Selenol‐Containing Biomolecules

A Raman spectroscopic study of the complexation of the methylmercury(II) cation by amino acids

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