Mercury(II) Cysteine Complexes in Alkaline Aqueous Solution
Bibliographic record
Abstract
Mercury(II) complexes with l-cysteine (H(2)Cys) in alkaline aqueous solutions have been structurally characterized by means of extended X-ray absorption fine structure (EXAFS) spectroscopy. The distribution of [Hg(Cys)(n)] (n = 2, 3, and 4) species in approximately 0.09 mol dm(-3) mercury(II) solutions with H(2)Cys/Hg(II) ratios varying from 2.2 to 10.1 has been evaluated by fitting linear combinations of simulated EXAFS functions for the separate complexes to the experimental EXAFS data, aided by (199)Hg NMR and Raman results. For the [Hg(Cys)(2)](2-) and [Hg(Cys)(3)](4-) complexes and the novel four-coordinated Hg(Cys)(4) species that dominates in solutions with excess of cysteine (H(2)Cys/Hg(II) > 5), the mean Hg-S bond distances were found to be 2.35(2), 2.44(2), and 2.52(2) Angstroms, respectively. The minor amount of the linear [Hg(Cys)(2)](2-) complex that can still be discerned in solutions with ratios up to H(2)Cys/Hg(II) = 5 was derived from the distinct S-Hg-S symmetric stretching Raman band at 334 cm(-1). From (199)Hg NMR spectra, the chemical shift of the Hg(Cys)(4) species was estimated to -340 ppm with an amount exceeding 85% in the highest excess of cysteine, consistent with the EXAFS data.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".