Solution behavior of Hg(II)-cystamine by Uv-Vis and¹⁹⁹Hg NMR

Abstract

The combination of HgCl 2 with the disulfide salt of 2-aminoethanethiol (cystamine dihydrogen dichloride) in water yields a two-dimensional chain { [HgCl 4 2þ (2). When compound 1 is combined with two equivalents of NaOH it rearranges to 2 as indicated by 199 Hg NMR and Uv-Vis.

Phosphonium Chloromercurate Room Temperature Ionic Liquids of Variable Composition

“…The 199 Hg NMR of this compound showed a peak at −1129 ppm relative to the standard at −1501 ppm, see Figure 1, second from top. The chemical shift found for (2) fits well with those published by Bharara 72 199 Hg NMR spectrum only shows one broad peak of low intensity with a maximum at −1118 ppm (Figure 1, third from top), which indicates a fast chloride exchange between the two different anions on the NMR time scale, as well as an oligomeric/polynuclear character. The peak's shape resembles the peak shape of the {HgCl 3 } − composition (4), indicating that higher adducts form (vide infra).…”

Mercury Magnetic Isotope Effect: A Plausible Photochemical Mechanism

“…Computed lowest singlet states for CH 3 HgSCH 3 and Hg(SCH 3 ) 2 have energies that match the absorption maxima of Hg−thiol complexes in the UVB/A region (Figure 4). 18,50,54,55 At the dissociation of the Hg−S bond in Hg(SCH 3 ) 2 , the 1,3 πσ* and 3 σσ* states are degenerate with the ground state, similar to the case of HgCl 2 photolysis. For CH 3 HgSCH 3 , only the dissociated 3 σσ* state is degenerate with the ground state, just as in CH 3 HgCl.…”

“…1 It has been suggested that CH 3 Hg in natural waters is predominately coordinated to thiol ligands 21−25 and the lowest singlet transition of CH 3 HgSCH 3 is available for photolysis in the UVB/A range. 18,50,54,55 The MgIE mechanism substantiated herein therefore can be used as a lens to examine the Hg cycle in the environment, providing deep insight into how biological samples of CH 3 Hg fractionate to mass-independent distributions.…”

Cystamindi-ium tetrachlorocuprate [NH3(CH2)2SS(CH2)2NH3][CuCl4]: synthesis, crystal structure, and thermal decomposition

“…The second was that the center symmetry was absent. The lack of coordination between the metal and sulfur atoms was detected on the example of CystaH 2 [HgCl 4 ] and described in detail in (Bharara et al, 2005b). It turned out that the reflexes forbidden in space group P2 1 /a supplied a good explanation of "impurity" reflexes on the experimental X-ray powder pattern.…”

“…Chlorine atoms of neighboring anions are oriented along the axis of the square plane complex [CuCl 4 ] 2− at a distance of 2.80(1) and 3.05(2) Å completing it to a distorted octahedron, [CuCl 6 ] 2− , which is more typical for copper crystallochemistry ( Figure 6). The lack of coordination between the metal and sulfur atoms was detected on the example of CystaH 2 [HgCl 4 ] and described in detail in (Bharara et al, 2005b). Saving S-S bonding was observed with the coordination centers as Pb, Bi, and V atoms (Pavani et al, 2006;Bi et al, 2007;Louvain et al, 2007).…”