Syntheses and vibrational spectra of some tris(alkanethiolato)mercurate(II) complexes, and crystal structure of the Hexakis(methanethiolato)dimercurate(II) dianion

Bowmaker, GA; Dance, Ian G.; Dobson, BC; Rogers, D.

doi:10.1071/ch9841607

Cited by 43 publications

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“…However, in the current study, EXAFS spectra were obtained for solutions A1 and A2 at room temperature in a wide k -range (up to 14.5 Å −1 ) and no such Hg⋯Hg scattering contribution could be observed (Figure S-4). In a survey of the Cambridge Structural Database (CSD, version 5.31, Nov. 2009) (35), we found dimeric complexes (such as COHWEB and DAXRAV) with two bridging thiolate groups, Hg 2 (μ-SR) 2 , leading to Hg II ⋯Hg II distances of ~ 3.6 Å (36, 37). Single oxygen bridges between two mercury(II) atoms have been found in several crystal structures, leading to Hg II ⋯Hg II distances of 3.5–3.6 Å (38).…”

Section: Discussionmentioning

confidence: 99%

Glutathione Complex Formation with Mercury(II) in Aqueous Solution at Physiological pH

Mah

Jalilehvand

2010

Chem. Res. Toxicol.

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The mercury(II) complexes formed in neutral aqueous solution with glutathione (GSH, here denoted AH3 in its tri-protonated form) were studied using Hg LIII-edge extended X-ray absorption fine structure (EXAFS) and 199Hg NMR spectroscopy, complemented with electrospray ionization mass spectrometric (ESI-MS) analyses. The [Hg(AH)2]2− complex, with the Hg-S bond distances 2.325 ± 0.01 Å in linear S-Hg-S coordination and the 199Hg NMR chemical shift −984 ppm, dominates except at high excess of glutathione. In a series of solutions with CHg(II) ~17 mM and GSH/Hg(II) mole ratios rising from 2.4 to 11.8, the gradually increasing mean Hg-S bond distance corresponds to an increasing amount of the [Hg(AH)3]4− complex. ESI-MS peaks appear at −m/z values of 1208 and 1230 corresponding to the [Na4Hg(AH)2(A)]− and [Na5Hg(AH)(A)2]− species, respectively. In another series of solutions at pH = 7.0 with CHg(II) ~50 mM and GSH/Hg(II) ratios from 2.0 to 10.0, the Hg LIII-edge EXAFS and 199Hg NMR spectra show that at high excess of glutathione (~0.35 mol·dm−3) about ~ 70% of the total mercury(II) concentration is present as the [Hg(AH)3]4− complex, with the average Hg-S bond distance 2.42 ± 0.02 Å in trigonal HgS3 coordination. The proportions of HgSn species, n = 2, 3 and 4, quantified by fitting linear combinations of model EXAFS oscillations to the experimental EXAFS data in our present and previous studies, were used to obtain stability constants for the [Hg(AH)3]4− complex, and also for the [Hg(A)4]10− complex that is present at high pH. For Hg(II) in low concentration at physiological conditions (pH = 7.4, CGSH = 2.2 mM) the relative amounts in the HgS2 species [Hg(AH)2]2−, [Hg(AH)(A)]3− and the HgS3 complex [Hg(AH)3]4− was calculated to be 95 : 2 : 3. Our results are not consistent with the formation of dimeric Hg(II)-GSH complexes proposed in a recent EXAFS study.

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Section: Discussionmentioning

confidence: 99%

Glutathione Complex Formation with Mercury(II) in Aqueous Solution at Physiological pH

Mah

Jalilehvand

2010

Chem. Res. Toxicol.

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“…From studies in which the 13C chemical shifts were measured as a function of the Hg(I1):GSH ratio at constant pH, it was shown that the differences are due to formation of the 3:l complex, Hg(g1~tathione)~. Evidence for the formation of Hg(SR)3-complexes, where R represents methyl and tert-butyl groups, in solution has also been obtained from vibrational spectroscopic studies (13). In another study, the crystalline mononuclear, three-coordinate mercury(I1) thiolate [NBun4:I [Hg(SPh)3] was prepared and its crystal structure determined (14).…”

Section: Methodsmentioning

confidence: 99%

“…4 to eq. [13] using nonlinear least-squares curve-fitting methods. The values used for (YRSH~SR, (YR'SH~SR,, (YRSH, and a,,,, in the curve fitting were calculated directly from sobs measured for solutions containing only these species.…”

Section: Displacement Equilibrium Constantsmentioning

confidence: 99%

Polarimetric and nuclear magnetic resonance studies of the complexation of mercury by thiols

Shoukry¹,

Cheesman²,

Rabenstein³

1988

Can. J. Chem.

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. Can. J. Chem. 66, 3184 (1988) The complexation of Hg(I1) by glutathione has been studied by polarimetry under conditions of excess ligand with the objective of characterizing formation of the 3: 1 complex, Hg(g1~tathione)~. The optical rotatory power of solutions containing glutathione only and of solutions containing glutathione and Hg(I1) at ratios of 2: 1,2.5: 1,3: 1, and 4: 1 was measured as a function of pH. Acid dissociation constants for the ammonium and thiol groups of glutathione and for the two ammonium groups of Hg(glutathi~ne)~ and the formation constant of the 3: 1 complex (Hg(g1~tathione)~ + glutathione a Hg(g1~tathione)~) were determined from the pH dependence of the optical rotatory power. The value obtained for the formation constant, K f = 1.5 x lo3, indicates that binding of the third ligand to form Hg(g1~tathione)~ is much weaker than binding of the first two glutathione ligands. However, calculations indicate that binding is sufficiently strong that a significant fraction of Hg(I1) is present as Hg(g1~tathione)~ under physiological conditions. Equilibrium constants were also determined by polarimetry and by I3c nuclear magnetic resonance for the displacement of one thiolate ligand by another (RSHgSR + R'SH RSHgSR' + RSH; RSHgSR' + R'SH R'SHgSR' + RSH). The results indicate that, at pH 5.5 and at physiological pH, the relative stability increases in the order Hg(g1utathi0ne)~ < Hg(peni~i1lamine)~ < Hg(mer~aptoethy1amine)~. However, when competitive protonation of free ligand is accounted for, it is shown that the intrinsic stability of the complexes increases in the order Hg(penicillamine)? < Hg(mer~aptoethy1amine)~ < Hg(glutathi~ne)~, which parallels the order of the Brgnsted basicity of the thiolate ligands. Chem. 66, 3184 (1988).Faisant appel B la polarimttrie et opCrant dans des conditions impliquant un excts de ligand, on a ttudiC la complexion du Hg(I1) par le glutathion dans le but de caracttriser la formation du complexe 3: 1, Hg(g1~tathion)~. On a mesurC la variation, en fonction du pH, du pouvoir rotatoire optique de solutions ne contenant que du glutathion ainsi que de solutions contenant du glutathion et du Hg(I1) ? i des rapports de 2: 1, 2.5: 1, 3: 1 et 4: 1. En se basant sur la relation entre le pouvoir rotatoire optique et le pH, on a dCterminC les constantes de dissociation acide des groupements ammonium et thiol du glutathion ainsi que des deux groupements ammonium du complexe Hg(glutathion)? de mCme que la constante de formation du complexe 3:1 (Hg(g1utathi0n)~ + glutathion a Hg(g1~tathion)~). La valeur obtenue pour la constante de formation, K f = 1,5 X lo3, indique que la liaison du troisitme ligand pour former le complexe Hg(g1~tathion)~ est beaucoup plus facile que les liaisons des deux premiers ligands glutathion. Toutefois, des calculs indiquent que la liaison est suffisamment forte pour qu'un fraction importante du Hg(I1) soit prtsent sous la forme Hg(gl~tathion)~, dans des conditions physiologiques. Faisant appel B la polarimCtrie ainsi que la resonance magnCtiq...

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“…With dithiolate ligands, an infinite chain of [H~,(scH,cH~s),]~-dianions is formed by 1,2-dithiolatoethane (47), while trans-l,2-dithiolatocyclohexane forms a dinuclear complex with Hg2S, core (48). Hg(SCH2-CH,CH2CH3), crystallizes with two HgS, tetrahedra linked by edge and corner sharing into helical chains (49), and the [H~~(scH,),]'-ion forms a centrosymmetric, doubly bridged dimer (50). Hg3S, cores are known (47,51), as are eightmembered Hg4S4 rings (43,52 For personal use only.…”

Section: The Synthesis Of the Hg Salt [(P-sc6h5)6{hgp(c6h5)3}mentioning

confidence: 99%

“…Bridging thiolate ligands are common, with a wide range of Hg-S distances. A search of the CSD (34) yielded thirteen entries describing a total of fifteen structures with (p2-SR) ligands (42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52). The structures of the complexes and geometries of the Hg-S-Hg bridges q e summarised in Table 5.…”

Section: The Synthesis Of the Hg Salt [(P-sc6h5)6{hgp(c6h5)3}mentioning

confidence: 99%

Metal-thiolate chemistry: The structure of the first adamantane-type cation, [(μ-SPh)₆(HgPPh₃)₄]²⁺

Vittal¹,

Dean²,

Payne³

1993

Can. J. Chem.

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The compound [(p-SC6H5)6{HgP(C6H5)3}4][C104]2 crystallizes in the $clinic space group pi as a bis(ch1oroform) solvate with cell dimensions a = 15.799(4), b = 26.813(5), c = 15.040(5) A, a = 96.35(2), P = 114.52(2), y = 100.45(2)" and two formula units per cell. The crystal and molecular structures of this salt were solved by X-ray diffraction techniques using 9898 counter data with I > 2.5a(I) recorded at -50(2)"C. Refinement of 477 variables by full-matrix leastsquares converged at an agreement factor R = 0.046. The cation has adarnantane-type stereochemistry with a (p-SPh)&g, cage and four terminal triphenylphosphine ligands. The S-C, vectors of the bridging SC6H5 groups adopt the configuration [aae, aae, aee, aee] with the minimum number of two 1,3-axial, axial substituent interactions. There is a significant flattening of the two Hg3S, rings with two axial substituents into an envelope conformation; each has two torsion angles less than 25", instead of the ideal values of 260" in adamantane. One perchlorate ion is doubly solvated by chloroform molecules in an unusual, weakly hydrogen bonded, [C104. 2HCC13]-complex.

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Syntheses and vibrational spectra of some tris(alkanethiolato)mercurate(II) complexes, and crystal structure of the Hexakis(methanethiolato)dimercurate(II) dianion

Cited by 43 publications

References 0 publications

Glutathione Complex Formation with Mercury(II) in Aqueous Solution at Physiological pH

Glutathione Complex Formation with Mercury(II) in Aqueous Solution at Physiological pH

Polarimetric and nuclear magnetic resonance studies of the complexation of mercury by thiols

Metal-thiolate chemistry: The structure of the first adamantane-type cation, [(μ-SPh)₆(HgPPh₃)₄]²⁺

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Syntheses and vibrational spectra of some tris(alkanethiolato)mercurate(II) complexes, and crystal structure of the Hexakis(methanethiolato)dimercurate(II) dianion

Cited by 43 publications

References 0 publications

Glutathione Complex Formation with Mercury(II) in Aqueous Solution at Physiological pH

Glutathione Complex Formation with Mercury(II) in Aqueous Solution at Physiological pH

Polarimetric and nuclear magnetic resonance studies of the complexation of mercury by thiols

Metal-thiolate chemistry: The structure of the first adamantane-type cation, [(μ-SPh)6(HgPPh3)4]2+

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Metal-thiolate chemistry: The structure of the first adamantane-type cation, [(μ-SPh)₆(HgPPh₃)₄]²⁺