Syntheses and Multi-NMR Study of <i>fac</i>- and <i>mer</i>-OsO<sub>3</sub>F<sub>2</sub>(NCCH<sub>3</sub>) and the X-ray Crystal Structure (<i>n</i> = 2) and Raman Spectrum (<i>n</i> = 0) of <i>fac</i>-OsO<sub>3</sub>F<sub>2</sub>(NCCH<sub>3</sub>)·<i>n</i>CH<sub>3</sub>CN
Bibliographic record
Abstract
Dissolution of the infinite chain polymer, (OsO<sub>3</sub>F<sub>2</sub>)<sub>∞</sub>, in CH<sub>3</sub>CN solvent at −40 °C followed by solvent removal under vacuum at −40 °C yielded <i>fac</i>-OsO<sub>3</sub>F<sub>2</sub>(NCCH<sub>3</sub>)·<i>n</i>CH<sub>3</sub>CN (<i>n</i> ≥ 2). Continued pumping at −40 °C with removal of uncoordinated CH<sub>3</sub>CN yielded <i>fac</i>-OsO<sub>3</sub>F<sub>2</sub>(NCCH<sub>3</sub>). Both <i>fac</i>-OsO<sub>3</sub>F<sub>2</sub>(NCCH<sub>3</sub>)·<i>n</i>CH<sub>3</sub>CN and <i>fac</i>-OsO<sub>3</sub>F<sub>2</sub>(NCCH<sub>3</sub>) are yellow-brown solids and were characterized by low-temperature (−150 °C) Raman spectroscopy. The crystal structure (−173 °C) of <i>fac</i>-OsO<sub>3</sub>F<sub>2</sub>(NCCH<sub>3</sub>)·2CH<sub>3</sub>CN consists of two co-crystallized CH<sub>3</sub>CN molecules and a pseudo-octahedral OsO<sub>3</sub>F<sub>2</sub>·NCCH<sub>3</sub> molecule in which three oxygen atoms are in a facial arrangement and CH<sub>3</sub>CN is coordinated trans to an oxygen atom in an end-on fashion. The Os---N bond length (2.205(3) Å) is among the shortest M---N adduct bonds observed for a d<sup>0</sup> transition metal oxide fluoride. The <sup>19</sup>F NMR spectrum of (OsO<sub>3</sub>F<sub>2</sub>)<sub>∞</sub> in CH<sub>3</sub>CN solvent (−40 °C) is a singlet (−99.6 ppm) corresponding to <i>fac</i>-OsO<sub>3</sub>F<sub>2</sub>(NCCH<sub>3</sub>). The <sup>1</sup>H, <sup>15</sup>N, <sup>13</sup>C, and <sup>19</sup>F NMR spectra of <sup>15</sup>N-enriched OsO<sub>3</sub>F<sub>2</sub>(NCCH<sub>3</sub>) were recorded in SO<sub>2</sub>ClF solvent (−84 °C). Nitrogen-15 enrichment resulted in splitting of the <sup>19</sup>F resonance of <i>fac</i>-OsO<sub>3</sub>F<sub>2</sub>(<sup>15</sup>NCCH<sub>3</sub>) into a doublet (<sup>2</sup><i>J</i>(<sup>15</sup>N−<sup>19</sup>F), 21 Hz). In addition, a doublet of doublets (<sup>2</sup><i>J</i>(<sup>19</sup>F<sub>ax</sub>−<sup>19</sup>F<sub>eq</sub>), 134 Hz; <sup>2</sup><i>J</i>(<sup>15</sup>N−<sup>19</sup>F<sub>eq</sub>), 18 Hz) and a doublet (<sup>2</sup><i>J</i>(<sup>19</sup>F<sub>ax</sub>−<sup>19</sup>F<sub>eq</sub>), 134 Hz) were observed in the <sup>19</sup>F NMR spectrum that have been assigned to <i>mer</i>-OsO<sub>3</sub>F<sub>2</sub>(<sup>15</sup>NCCH<sub>3</sub>); however, coupling of <sup>15</sup>N to the axial fluorine-on-osmium environment could not be resolved. The nitrogen atom of CH<sub>3</sub>CN is coordinated trans to a fluorine ligand in the <i>mer</i>-isomer. Quantum-chemical calculations at the SVWN and B3LYP levels of theory were used to calculate the energy-minimized gas-phase geometries, vibrational frequencies of <i>fac</i>- and <i>mer</i>-OsO<sub>3</sub>F<sub>2</sub>(NCCH<sub>3</sub>) and of CH<sub>3</sub>CN. The relative stabilities of the <i>mer</i>- and <i>fac</i>-isomers have been determined and are in accordance with the solution NMR assignments.
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How this classification was reachedexpand
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 | 0.027 | 0.025 |
| Meta-epidemiology (narrow) | 0.051 | 0.051 |
| Meta-epidemiology (broad) | 0.049 | 0.023 |
| Bibliometrics | 0.023 | 0.033 |
| Science and technology studies | 0.026 | 0.027 |
| Scholarly communication | 0.018 | 0.023 |
| Open science | 0.044 | 0.035 |
| Research integrity | 0.036 | 0.030 |
| Insufficient payload (model declined to judge) | 0.023 | 0.012 |
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; both teacher heads agree on what is shown here.
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".