Interaction between Se and In,and distribution of Zn in mice injected with indium ions and selenium compounds

Male Swiss mice were injected intraperitoneally with indium ions and Se-compounds (viz. selenomethionine and SeO₂). The distribution of Se, In and Zn in liver and spleen has been studied by instrumental neutron activation analysis. Se and In were incorporated in all investigated organs. The simultaneous injections with In and Se-compounds do not produce observable In–Se correlations effects. On the other hand, it was found that the simultaneous and single In injections increase the Zn-content in liver (24 h after injections), whereas no correlation effects were observed in spleen.     

Effect of sulfur compounds and uranium on the distribution of Se in mice studied by instrumental neutron activation analysis

The incorporation of Se into some mice organs after injections of seleno-cystamine [(Se-Cta)₂] in the presence of glutathione, cysteine, methionine, cysteamine, 6-mercaptopurine, 2-mercaptopurine and UO ₂ ²⁺ has been studied. Variations in the Zn, Rb, Co, Fe and Hg contents were determined in all examined organs after intraperitoneal injections with the above compounds. Instrumental neutron activation analysis was applied as the analytical method. It was found that injected compounds affect the Se-distribution in the organs examined. Single applied intraperitoneal injection of (Se-Cta)₂ or UO ₂ ²⁺ lead to variations in the Zn, Rb, Co, Fe and Hg contents in mice organs.     

Use of INAA to study the interaction between Ag and Se,Zn, Rb,Fe or Co in mice

The interaction of inorganic silver (as AgNO₃) with SeO₂ and Se-compounds was studied. Instrumental neutron activation analysis (INAA) was applied as the analytical method. Organ concentrations of Ag were always significantly higher 72 hours after simultaneous intraperitoneal injections with AgNO₃ and Se-compounds. Moreover, simultaneous injections elevated the Se-content in organs examined. We suggest that Se-compounds protect against liver lesions by markedly decreasing the concentration of Ag in this organ 2 hours after simultaneous injections. It was also found that Ag supply affects the contents of Zn, Rb, Fe and Co.     

Studies on the incorporation of Se and Te in the presence of glutathione and cysteine and the distribution of Hg,Zn, Fe,Co and Rb in mice by instrumental neutron activation analysis

The incorporation of Se or Te into some mice organs after injections with selenodiglutathione [(GS)₂ Se], seleno-cystine [(CySe)₂] or Na₂TeO₃ in the presence of glutathione (GSH) or cysteine (CySH) has been studied. Variations in the Hg, Zn, Fe, Co, and Rb contents were determined in all the investigated organs after intraperitoneal injections with the above compounds. Instrumental neutron activation analysis was applied as the analytical method. It was found that GSH and CySH increased the Se-content in the organs after the injection with (CySe)₂, whereas GSH decreased after (GS)₂ Se supply. GSH and CySH changed also the Te distribution. Injections with the above compounds affect the Hg, Zn, Fe, Co and Rb concentrations and these variations depend upon the injected compounds.     

Interaction between Se and Cr and distribution of Zn,Rb, Co,and Fe in mice given chromate ions and selenium compounds

Male SAS/4 mice injected intraperitoneally with chromate ions and Se-compounds (i.e. selenodiglutathione, selenocystine, selenomethionine and SeO₂). The distribution of Se, Cr, Zn, Rb, Co and Fe in liver, kidneys, spleen, heart, lungs, blood, small intestine and eyes has been studied by instrumental neutron activation analysis. Cr was incorporated in all investigated organs and the efficiency of the Cr-accumulation was affected upon the Se-injection. It was found that the mutual and indirect interaction occurs between injected Se-compounds and chromate ions. On the other hand, the interaction of Cr with Zn has been competitive. Injection with chromate ions affects the contents of Rb, Co and Fe in mice organs.     

Effect of selenium on the Hg,Zn, Fe and Co content of yeast cells

The yeast cells, Saccharomyces cerevisiae, were exposed to Hg²⁺ ions (10^–4M) and SeO₂ (2·10^–4–10^–2M) or Se- methionine (2·10^–4M). Instrumental neutron activation analysis (INAA) was used to analyze changes in the Hg, Zn, Fe and Co levels in these cells. When the yeast was incubated in a medium containing 10^–3M and 10^–2M SeO₂, the Hg content of the yeast markedly increased. It was also found that the uptake of Se and Hg influenced the levels of Zn, Fe and Co found in the cells. While the presence of Se-methionine (Se-Met), SeO₂ or Hg²⁺ ions caused increases in the intracellular Zn levels, the combined presence of Hg²⁺ and SeO₂ and their assumed interaction, reduced the efficiency of Se for increasing the Zn content of yeast.     

Studies on the incorporation of Se in the presence of glutathione and the distribution of Zn,Co, Fe,Rb and Cs in mice by instrumental neutron activation analysis

The contents of Se, Fe, Co, Zn and Rb in several organs of Swiss mice were determined by instrumental neutron activation analysis (INAA) after injections with seleno-methionine (Se-Met) and glutathione (GSH). Se was accumulated in all examined organs and significant effects of the treatment with GSH on the distribution of Se were observed. An increase of Zn (or Se) content in blood after injection with Se-Met (or Zn²⁺ ions) was observed.     

Kinetics of the Hg(II)/Hg electrode reaction in DMSO solutions of chloride ions

The electrode reaction Hg(II)/Hg in complex chloride solutions with dimethyl sulfoxide as solvent has been investigated at the equilibrium potential by the faradaic impedance method and a cyclic current-step method. The ionic strength was 1 M with ammonium perchlorate as supporting electrolyte, and the temperature was 25°C. Double-layer data have been determined by electrocapillary measurements. From the results of the kinetic measurements at ligand numbers ≤1.1 or ≥2.3 it is concluded that the overall charge transfer proceeds step-wise. The solvated Hg²⁺ and Hg₂²⁺ as well as the complexes HgCl_j^2?j and the dinuclear Hg₂Cl³⁺ contribute to the exchange current density. The rate constant of the step HgCl_j^2?j/ Hg(I) is found to increase with the number of Cl^? coordinated. This increase can be correlated to a decrease in solvation and a lengthening of the Hg?Cl distance. For 1.1 << 2.3, impedance measurements indicate a rate-controlling adsorption step. It is suggested that the uncharged HgCl₂ then forms an adsorbed network on the mercury surface.     

Theoretical and Experimental Study of Pb2+ and Hg2+ Adsorption on Biopolymers, 1. Theoretical Study

Chitosan and pectic acid have been modeled as disaccharides or oligosaccharides for Hg²⁺ and Pb²⁺ adsorption. Reasonable models of both biopolymers were used. Several adsorption sites of both polysaccharides were considered, mainly NH₂ in chitosan and CO₂^– in pectic acid. Hg²⁺ has several points of anchorage on chitosan. The most important one is NH₂ . The Molecular Mechanic modeling permit us to compare in relative terms the different conformations of models of pectic acid and chitosan and their effect in heavy metal coordination. Using the Parameterized Model version 3 (PM3), we report the formation enthalpy of inter‐ and intramolecular compounds with Hg and Pb. The Extended Huckel method (EHM) results seem to indicate that electrostatic interaction (leading to adsorbed cation on NH₂ and on sites different to NH₂) could be the reason for the high uptake found for Hg²⁺ using chitosan. Besides NH₂, the OH near the amine group is the preferred site for Hg²⁺ adsorption, especially if it is ionized. In the case of Pb²⁺ adsorption, several sites of chitosan present no interaction with this cation. Only the NH₂ group and the ionized OH group mentioned above seem to be the preferred sites, following the EH modified (EHMO) results. The Hg‐ and Pb‐adsorption modeling on pectic acid permit us to conclude that the best site is the same for both metals: the bridge oxygen between monomers of galacturonic acid. the carbonyl group from carboxylate is the best second site for Hg²⁺, whereas the internal oxygen bridge is the best second site for Pb²⁺. Considering the Hg ²⁺ chemistry in aqueous solution, we evaluated the HgOH⁺ and HgCl⁺ or HgCl₃^– adsorption on both copolymers, using EHMO. The energetic of adsorption changed on both biopolymers for these species, comparing them with Hg²⁺.     

Crystal structure determination of complexes of monomethylammonium chloride and mercury(II) chloride: CH3NH3HgCl3, (CH3NH3)2HgCl4, and CH3NH3Hg2Cl5

The crystal structures have been determined of CH₃NH₃HgCl₃, (CH₃NH₃)₂HgCl₄, and CH₃NH₃Hg₂Cl₅. In (CH₃NH₃)₂HgCl₄ the Hg^II atom is tetrahedrally coordinated by four Cl atoms with Hg? Cl bond lengths of 2.464 to 2.478 Å. In the other two compounds the Hg^II atom is involved in two short covalent Hg? Cl bonds, forming a pseudo HgCl₂ molecule and two much longer bridging Hg? Cl bonds. The methylammonium groups are connected by hydrogen bonds to the chlorine atoms. The nature of the hydrogen bonding scheme probably causes disorder of the methylammonium groups.     

Studies on the interaction between Se,Te, Cd,As and Zn and the distribution of Fe,Co, Rb and Hg in mice by instrumental neutron activation analysis

The incorporation of Se and Te into liver, kidneys, heart, spleen, lung and small intestine after i.p. injections of Balby mice with seleno-cystine (CySe)₂ and Na₂TeO₃ in the presence of Cd (as CdCl₂), As (as As₂O₃) and Zn (as ZnSO₄) has been studied. The change of contents of Co, Fe, Rb and Hg were determined in all investigated organs after injections with the above compounds. Instrumental neutron activation analysis was applied as the analytical method. It was found that a competitive interaction occurs between As and Se or Te. Similarly, this interaction has been observed between Se and Cd. The data obtained suggest that Cd has a higher competitive ability to displace Te than Zn and Se. Injection with the above compounds affects the contents of Fe, Co, Rb and Hg in all mice organs.     

Untersuchungen über das Gleichgewicht des Hg2+-Hg 2 2+ -Hg-Systems in konzentrierten Perchloratlösungen

The formal potentials of the Hg²⁺/Hg ₂ ²⁺ , Hg ₂ ²⁺ /Hg and Hg²⁺/Hg redox couples and the apparent equilibrium constants of the reaction Hg²⁺ + Hg ∝ Hg ₂ ²⁺ in conc. aqueous solutions of Mg(ClO₄)₂ and Ca(ClO₄)₂ have been determined from emf measurements performed using cells with liquid junction. Based on these data, the hydration numbers of the Hg²⁺ and Hg ₂ ²⁺ ions were estimated.     

Determination of inorganic and methylmercury in fish by cold vapor atomic absorption spectrometry and inductively coupled plasma atomic emission spectrometry

Simple and rapid analytical procedures for the determination of Hg²⁺ and methylmercury in fish were proposed after careful optimization of chemical and instrumental parameters for Hg measurement by cold vapor (CV)/hydride generation (HG) atomic absorption spectrometry (AAS) and CV/HG inductively coupled plasma atomic emission spectrometry (ICP-AES). Quantitative extraction of Hg species avoiding any inter-species conversion was achieved by fast microwave assisted solubilization of fish tissue with relatively low amount of tetramethylammonium hydroxide (TMAH) or 6 mol L^− 1 HCl. After careful optimization of chemical parameters selective determination of Hg²⁺ in the presence of excess of methylmercury is attained by using continuous flow CV AAS, 1% m/V SnCl₂ as reductant and 0.1 mol L^− 1 HCl as reaction medium. Simple calibration curve prepared with aqueous standard of Hg²⁺ is recommended for its quantification. Both Hg²⁺ and methylmercury could be determined simultaneously with equal sensitivity by CV/HG ICP-AES directly in the diluted TMAH solution obtained after extraction with 1% m/V NaBH₄ as reductant. Quantification of the sum of Hg²⁺ and methylmercury against calibration curve prepared with aqueous standard of methylmercury is suggested. It should be mentioned that batch hydride generation system with quartz tube heated in air/acetylene flame could also be used for simultaneous determination of both Hg species in fish extracts, with standard additions calibration. The validity of the developed analytical procedures for selective determination of Hg²⁺ and methylmercury (by difference between the total Hg and Hg²⁺) is confirmed by the analyses of certified reference material DOLT-1 and reference material IMEP-20. Very close agreement between certified values and analytical results was found.     

Uptake of inorganic Hg by organically modified silicates: influence of pH and chloride concentration on the binding pathways and electrochemical monitoring of the processes

Transport of mercury species in aquatic media is strongly affected by sorption processes on both organic and inorganic particles, and such mass transfer reactions are governed by speciation of this contaminant in the environment. The present research investigates the uptake of inorganic Hg^II species by sorbent materials based on polysiloxane-immobilized amine or thiol ligands, with the goal to highlight the effect of speciation on the sorption processes. Mercury binding was studied as a function of pH and chloride concentration to cover a wide range of species, including some among the most widely encountered forms in natural medium (HgCl₄²⁻, HgCl₃⁻, HgCl₂, Hg(OH)₂). It was found on the one hand that all these species are liable to be removed from solution by strong binding to silica gels grafted with mercaptopropyl groups. On the other hand, the use of silica bearing aminopropyl moieties has led to the selective accumulation of anionic chloro-complexes of Hg^II in acidic medium in the presence of high chloride concentration and to the uptake of Hg^II hydroxide around neutral pH, while HgCl₂ cannot be adsorbed on this material. The former reaction involves electrostatic interactions between HgCl₄²⁻ or HgCl₃⁻ and the ammonium form of polysiloxane-immobilized amine ligands, and the latter is driven by complexation of Hg^II species to the unprotonated amine groups. The interest of electrochemistry at carbon paste electrodes modified with these adsorbents for characterizing the sorption processes was also described by applying the following sequence “voltammetric detection subsequent to open-circuit accumulation”. This approach allows the in situ determination of the amount of mercury in the organic-inorganic hybrid phase, as a function of speciation in solution and without significant modification in the solution-phase concentrations, so that the adsorption and ion-exchange isotherms can be obtained very easily and without requiring additional treatment of the solid material.     

Direct Detection of Solid Inorganic Mercury Salts at Ambient Pressure by Electron-Capture and Reaction-Assisted HePI Mass Spectrometry

Solid HgCl₂ is readily detected at ambient conditions by electron capture in a HePI-MS source. The captured electron occupies the empty 6 s orbital of the Hg atom. The resulting radical-anion HgCl₂ ^?? can exist as three “flexomers” of different Cl-Hg-Cl angle. The facile in-source formation of HgCl₂ ^?? and the adduct [HgCl₃]^–- is exploited to detect other solid Hg compounds by exposing them to an external chloride source, such as HCl, NaCl, or vapors emanating from solid TiCl₃. In situ oxidation of Hg₂Cl₂ with H₂O₂ generated signals for HgCl₂ ^?? and [HgCl₃] ^–, suggesting that oxidation makes Hg 6 s orbital available for electron capture.

Analysis of inorganic mercury species associated with airborne particulate matter/aerosols: method development

This paper describes a method for speciation of Hg associated with airborne particulate matter. This method uses a mini-sampler for sample collection and analysis, thermal desorption for separating Hg species, and inductively coupled plasma mass spectrometry (ICP–MS) for identification and quantification of Hg. Coal fly ash spiked with different Hg compounds (e.g. Hg⁰, HgCl₂, HgO, and HgS) was used for qualitative calibration. A standard reference material with a certified value for Hg concentration was used to evaluate the method. When the temperature of the furnace was programmed at a linear rate of increase of 50° min^–1, different Hg compounds could clearly be separated. Three airborne particulate matter samples were collected in parallel in Toronto, ON, Canada and analyzed using this method. Reproducible results were obtained and Hg⁰, HgCl₂, HgO, and HgS species from these samples were detected.     

Photophysical characteristics and density functional theory calculations of indole 2-carboxylic acid in the presence of mercurous ions

Many photo-physical studies have been reported for the detection of Hg²⁺ ions. Here we present the effect of Hg ₂ ²⁺ ions on the absorption and fluorescence of indole-2-carboxylic acid (I2C). Experimental evidence, supported by density functional theory B3LYP/LANL2DZ/PCM, for the formation of a I2C-Hg ₂ ²⁺ complex, is reported for the first time. It was observed that I2C forms a ground-state complex with Hg ₂ ²⁺ ions in a ratio of 3:1. The possibility of I2C to be used as a selective novel chemical sensor for the spectrophotometric detection of mercurous ions is described.     

Near‐Infrared‐Emitting CdxHg1−xSe Nanorods Fabricated by Ion Exchange in an Aqueous Medium

Whereas CdSe nanorods that are grown in organic solution have a hexagonal wurtzite structure, which is the limiting case for exchange, HgSe is more commonly encountered as a cubic zinc blende system. An exchange process was performed at room temperature and at atmospheric pressure in an aqueous environment after phase transfer of the original CdSe nanorods, which reinforced the tendency for the endpoint of HgSe to be cubic. Consequently, we observed that under ambient conditions, the exchange process terminated with an average composition of only Cd_0.9Hg_0.1Se. Following the changes during the process by optical spectroscopy and high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM), we observed that the Hg²⁺ ions diffused into the rods to a point limited by the formation of stacking faults due to the different lattice structures of the two limiting cases of zinc blende and wurtzite. HAADF‐STEM and energy dispersive spectroscopy analyses also confirmed that the Hg substitution did not occur uniformly throughout the individual nanorods, as Hg‐poor and Hg‐rich regions coexist around the stacking faults. The formation of near‐infrared‐emitting alloyed Cd_xHg_1?xSe nanorods in an aqueous medium highlights the subtle dependence of the ion‐exchange process on the differences in the crystal structures of the two endpoint lattices.     

Structural characterization of the derivatives of bis{[2,6‐(dimethylamino)methyl]phenyl} selenide with palladium(II) and mercury(II)

The intramolecularly coordinated homoleptic diorgano selenide bis{2,6‐bis[(dimethylamino)methyl]phenyl} selenide, C₂₄H₃₈N₄Se or R₂Se, where R is 2,6‐(Me₂NCH₂)₂C₆H₃, 14 , was synthesized and its ligation reactions with Pd^II and Hg^II precursors were explored. The reaction of 14 with SO₂Cl₂ and K₂PdCl₄ resulted in the formation of the meta C—H‐activated dipalladated complex {μ‐2,2′‐bis[(dimethylamino)methyl]‐4,4′‐bis[(dimethylazaniumyl)methyl]‐3,3′‐selanediyldiphenyl‐κ⁴C¹,N²:C^1′,N^2′}bis[dichloridopalladium(II)], [Pd₂Cl₄(C₂₄H₃₈N₄Se)] or [{R(H)PdCl₂}₂Se], 15 . On the other hand, when ligand 14 was reacted with HgCl₂, the reaction afforded a dimercurated selenolate complex, {μ‐bis{2,6‐bis[(dimethylamino)methyl]benzeneselanolato‐κ⁴N²,Se:Se,N⁶}‐μ‐chlorido‐bis[chloridomercury(II)], [Hg₂(C₁₂H₁₉N₂Se)Cl₃] or RSeHg₂Cl₃, 16 , where two Hg^II ions are bridged by selenolate and chloride ligands. In palladium complex 15 , there are two molecules located on crystallographic twofold axes and within each molecule the Pd moieties are related by symmetry, but there are still two independent Pd centers. Mercury complex 16 results from the cleavage of one of the Se—C bonds to form a bifurcated SeHg₂ moiety with the formal charge on the Se atom being ?1. In addition, one of the Cl ligands bridges the two Hg atoms and there are two terminal Hg—Cl bonds. Each Hg atom is in a distorted environment which can be best described as a T‐shaped base with the bridging Cl atom in an apical position, with several angles close to 90° and with one angle much larger and closer to 180°.     

Molecular Assembly Directed by Metal–Aromatic Interactions: Control of the Aggregation and Photophysical Properties of Zn–Salen Complexes by Aromatic Mercuration

There is widespread interest in non‐covalent bonding and weak interactions, such as electrostatic interactions, hydrogen bonding, solvophobic/hydrophobic interactions, metal–metal interactions, and π–π stacking, to tune the molecular assembly of planar π‐conjugated organic and inorganic molecules. Inspired by the roles of metal–aromatic interaction in biological systems, such as in ion channels and metalloproteins, herein, we report the first example of the use of Hg²⁺–aromatic interactions to selectively control the assembly and disassembly of zinc–salen complexes in aqueous media; moreover, this process exhibited significant “turn on” fluorescent properties. UV/Vis and fluorescence spectroscopic analysis of the titration of Hg²⁺ ions versus complex ZnL¹ revealed that the higher binding affinity of Hg²⁺ ions (compared to 13 other metal ions) was ascribed to specific interactions between the Hg²⁺ ions and the phenyl rings of ZnL¹ ; this result was also confirmed by ¹H NMR spectroscopy and HRMS (ESI). Further evidence for this type of interaction was obtained from the reaction of small‐molecule analogue L¹ with Hg²⁺ ions, which demonstrates the proximity of the N‐alkyl group to the aromatic protons during Hg²⁺‐ion binding, which led to the consequential H/D exchange reaction with D₂O. DFT modeling of such interactions between the Hg²⁺ ions and the phenyl rings afforded calculated distances between the C and Hg atoms (2.29 Å) that were indicative of C? Hg bond‐formation, under the direction of the N atom of the morpholine ring. The unusual coordination of Hg²⁺ ions to the phenyl ring of the metallosalen complexes not only strengthened the binding ability but also increased the steric effect to promote the disassembly of ZnL¹ in aqueous media.