X-ray-Induced Photoreduction of Hg(II) in Aqueous Frozen Solution Yields Nearly Monatomic Hg(0)

Nienaber, Kurt H.; Nehzati, Susan; Cotelesage, Julien J. H.; Pickering, Ingrid J.; George, Graham N.

doi:10.1021/acs.inorgchem.8b00694

Cited by 4 publications

(4 citation statements)

References 32 publications

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“…In agreement with this, the bond-lengths to the methyl groups are 1.475(3) and 1.497(3) for N–C and C–C, respectively, and these compare well with other methyl-thymidine structures in the Cambridge Structural Database, which gives mean N–C and C–C values of 1.479 and 1.494 Å, respectively. Our computational studies are in excellent agreement with the crystal structure data, with an Hg–N3 bond-length of 2.0150 Å for the antiperiplanar conformation: an agreement of better than 0.01 Å, emphasizing the capabilities of the M11-L functional within the meta-GGA approximation, which we previously observed . Also, in agreement with our computational studies, discussed above, the refinement of the 1-methylthymine group in our structure closely matches the crystal structure of pure 1-methylthymine, showing differences of less than 1° for all bond-angles, suggesting only minimal distortions upon Hg complexation.…”

Section: Resultssupporting

confidence: 90%

“…Our computational studies are in excellent agreement with the crystal structure data, with an Hg−N3 bond-length of 2.0150 Å for the antiperiplanar conformation: an agreement of better than 0.01 Å, emphasizing the capabilities of the M11-L functional within the meta-GGA approximation, which we previously observed. 48 Also, in agreement with our computational studies, discussed above, the refinement of the 1-methylthymine group in our structure closely matches the crystal structure of pure 1-methylthymine, 49 showing differences of less than 1°for all bond-angles, suggesting only minimal distortions upon Hg complexation.…”

Section: Resultssupporting

confidence: 89%

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Hg(II) Binding to Thymine Bases in DNA

et al. 2021

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The compounds of mercury can be highly toxic and can interfere with a range of biological processes, although many aspects of the mechanism of toxicity are still obscure or unknown. One especially intriguing property of Hg(II) is its ability to bind DNA directly, making interstrand cross-links between thymine nucleobases in AT-rich sequences. We have used a combination of small molecule X-ray diffraction, X-ray spectroscopies, and computational chemistry to study the interactions of Hg(II) with thymine. We find that the energetically preferred mode of thymine binding in DNA is to the N3 and predict only minor distortions of the DNA structure on binding one Hg(II) to two cross-adjacent thymine nucleotides. The preferred geometry is predicted to be twisted away from coplanar through a torsion angle of between 32 and 43°. Using 1-methylthymine as a model, the bis-thymine coordination of Hg(II) is found to give a highly characteristic X-ray spectroscopic signature that is quite distinct from other previously described biological modes of binding of Hg(II). This work enlarges and deepens our view of significant biological targets of Hg(II) and demonstrates tools that can provide a characteristic signature for the binding of Hg(II) to DNA in more complex matrices including intact cells and tissues, laying the foundation for future studies of mechanisms of mercury toxicity.

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Section: Resultssupporting

confidence: 90%

Section: Resultssupporting

confidence: 89%

Hg(II) Binding to Thymine Bases in DNA

et al. 2021

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“…The occurrence of Hg(I) has been observed in a variety of artificial and natural environments using techniques such as X-ray absorption spectrometry, , X-ray photoelectron spectrometry, X-ray diffraction, Raman spectrometry, and thermal desorption atomic absorption spectrometry. − Unfortunately, the poor sensitivity and uncontrolled transformation of Hg(I) under X-ray, lasers, or thermal irradiation inevitably limit the applicability of these methods. − To include Hg(I) in Hg speciation scheme, a protocol combining a mild extraction using 2-mercaptoethanol (2-ME) with sensitive liquid chromatography–inductively coupled plasma mass spectrometry (LC-ICPMS) was developed to identify Hg(I) in environmental solid matrices, such as soil and atmospheric particulate matter . However, the occurrence of Hg(I) in aquatic environments, which are hotspots for Hg transformations, remains unknown.…”

Section: Introductionmentioning

confidence: 99%

Transformation of Mercurous [Hg(I)] Species during Laboratory Standard Preparation and Analysis: Implication for Environmental Analysis

Fang,

Liu,

Wang

et al. 2024

Environ. Sci. Technol.

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Hg(I) may control Hg redox kinetics; however, its metastable nature hinders analysis. Herein, the stability of Hg(I) during standard preparation and analysis was studied. Gravimetric analysis showed that Hg(I) was stable in its stock solution (1000 mg L −1 ), yet completely disproportionated when its dilute solution (10 μg L −1 ) was analyzed using liquid chromatography (LC)-ICPMS. The Hg(I) dimer can form through an energetically favorable comproportionation between Hg(0) and Hg(II), as supported by density functional theory calculation and traced by the rapid isotope exchange between 199 Hg(0) aq and 202 Hg(II). However, the separation of Hg(0) and Hg(II) (e.g., LC process) triggered its further disproportionation. Polypropylene container, increasing headspace, decreasing pH, and increasing dissolved oxygen significantly enhanced the disproportionation or redox transformations of Hg(I). Thus, using a glass container without headspace and maintaining a slightly alkaline solution are recommended for the dilute Hg(I) stabilization. Notably, we detected elevated concentrations of Hg(I) (4.4−6.1 μg L −1 ) in creek waters from a heavily Hg-polluted area, accounting for 54−70% of total dissolved Hg. We also verified the reductive formation of Hg(I) in Hg(II)-spiked environmental water samples, where Hg(I) can stably exist in aquatic environments for at least 24 h, especially in seawater. These findings provide mechanistic insights into the transformation of Hg(I), which are indicative of its further environmental identification.

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“…However, currently available analytical methods cannot fully meet the requirement of Hg(I) analysis in artificial and natural environments due to the thermodynamically unstable nature of Hg(I) and the low concentration of total Hg. Although extended X-ray absorption fine structure, X-ray photoelectron spectroscopy, X-ray diffraction, and Raman spectroscopy , could be used for Hg(I) species identification, poor sensitivity and X-ray/laser-induced Hg species transformation largely limit their applications. − In the gas chromatographic analysis, both the high temperature of the injection port and the alkylation derivatization process result in significant oxidation of Hg(I). Thermal desorption atomic spectroscopy is widely used for speciation analysis of Hg in solid matrices.…”

Section: Introductionmentioning

confidence: 99%

Occurrence of Mercurous [Hg(I)] Species in Environmental Solid Matrices as Probed by Mild 2-Mercaptoethanol Extraction and HPLC-ICP-MS Analysis

Wang

Liu

et al. 2020

Environ. Sci. Technol. Lett.

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Mercurous Hg [Hg(I)] is, from the perspective of chemistry, an inevitable intermediate in Hg(II)/Hg(0) redox, presumably playing a critical role in the environmental transformation of common toxic Hg species, such as Hg(II), Hg(0), and methylmercury. The occurrence of Hg(I) in the environment, however, has been scarcely documented, due to its instability, which greatly limits its isolation and identification. We probed the occurrence of Hg(I) in various environmental solid matrices by developing and employing a method based on mild 2mercaptoethanol extraction and HPLC-ICP-MS analysis. Various complexation agents and assisted extraction methods were investigated for their effects on Hg(I) stability. A variety of solid matrices were used to demonstrate extraction, separation, and detection of Hg(I) under optimized conditions. The occurrence of Hg(I) was widely evident in various solid matrices, including desulfurized gypsum, fly ash, phosphorus powder in used fluorescent lamps, PM 2.5 , soil, and plants, despite Hg(I) reduction possibly being catalyzed by a solid matrix during extraction that could underestimate Hg(I) in the samples. More importantly, Hg(I) was detected in Hg(II)-exposed microalgae, exemplifying the environmental relevance of Hg(II) to Hg(I) transformation. These findings highlight the environmental significance of Hg(I), which should be further studied to examine the role of Hg(I) in the transformation, bioavailability, and toxicity of Hg.

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X-ray-Induced Photoreduction of Hg(II) in Aqueous Frozen Solution Yields Nearly Monatomic Hg(0)

Cited by 4 publications

References 32 publications

Hg(II) Binding to Thymine Bases in DNA

Hg(II) Binding to Thymine Bases in DNA

Transformation of Mercurous [Hg(I)] Species during Laboratory Standard Preparation and Analysis: Implication for Environmental Analysis

Occurrence of Mercurous [Hg(I)] Species in Environmental Solid Matrices as Probed by Mild 2-Mercaptoethanol Extraction and HPLC-ICP-MS Analysis

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