Sulfur K-edge X-ray absorption near-edge spectral analysis of thiourea free ligand and its Zn(II), Co(II), and Ni(II) complexes
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Bibliographic record
Abstract
<em>Electronic supporting information for the analysis and interpretation of sulfur K-edge X-ray absorption near-edge spectra of thiourea free ligand and its [Zn(TU)<sub>4</sub>]<sup>2+</sup>, [Co(TU)<sub>4</sub>]<sup>2+</sup>, and [Ni(TU)<sub>6</sub>]<sup>2+</sup> complexes.</em> Sulfur K-edge X-ray absorption spectroscopy (XAS) was employed to experimentally define the nature of coordinative bond between thiourea (TU) or thiocarbamide ligand and Zn<sup>2+</sup>, Co<sup>2+</sup>, and Ni<sup>2+ </sup>ions in distorted tetrahedral and octahedral homoleptic coordination environments. Comparisons of XAS spectra of the free TU ligand, [Zn(TU)<sub>4</sub>]<sup>2+</sup>, [Co(TU)<sub>4</sub>]<sup>2+</sup>, and [Ni(TU)<sub>6</sub>]<sup>2+</sup> complexes clearly identify spectral features emerging from the structural non-innocent TM<sup>2+</sup>–S(TU) bonding. Quantitative analysis of pre-edge intensities describes the covalency of Ni<sup>2+</sup>– and Co<sup>2+</sup>–S(TU) bonding to be at most 23% and 9% as expressed by the S 3p contributions per 3d electron hole. Using relevant Ni<sup>2+</sup> complexes with dithiocarbamate and thioether ligands, we evaluated the empirical S 1s→3p transition dipole integrals developed for sulfur ligands and its dependence on heteroatom substitutions. With the aid of density functional theory-based ground electronic state calculations, we found evidence for the need of using a transition dipole that is dependent on the presence of conjugated heteroatom (N) substitution in the S-ligands. <em>Table of Contents:</em> Worksheets "transition dipole" and "spectral modeling summary" contain data for empirical S 1s->3p transition dipole integral estimates and summary of spectral modeling, respectively. <strong>RAW_DATA folder:</strong><br> ASCII formatted S K-edge XAS data from BL 4-3 of SSRL, and data obtained for the [Ni(TU)<sub>6</sub>]<sup>2+</sup> complex at the double-crystal monochromator beamline (formerly Canadian Beamline) of Synchrotron Research Center (the home of Aladdin), in Stoughton, Wisconsin. <strong>SPECTRAL_MODELS folder</strong><br> Electronic spreadsheets, PeakFit spectral fitting templates, spectra as user-defined functions, quantitative analysis of pre-edge feature intensities <strong>XRD_STRUCTURES folder</strong><br> Xmol (XYZ) and DSViewerPro (MSV) files for the analysis of the crystal packing environment of TU complexes. <strong>DFT_CALCULATIONS</strong><br> Gaussian09 log files for free thiourea, Co<sup>(II)</sup> and Ni<sup>(II)</sup> complexes at BP86/def2TZVP, B3LYP/def2TZVP, and TPSS/def2TZVP levels of theory; frequency calculations for IR vibrational spectral simulations.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.002 | 0.000 |
| Open science | 0.002 | 0.007 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.023 | 0.001 |
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 it