Synthesis and Lewis Acid Properties of (ReO<sub>3</sub>F)<sub>∞</sub> and the X-ray Crystal Structures of (HF)<sub>2</sub>ReO<sub>3</sub>F·HF and [N(CH<sub>3</sub>)<sub>4</sub>]<sub>2</sub>-[{ReO<sub>3</sub>(μ-F)}<sub>3</sub>(μ<sub>3</sub>-O)]·CH<sub>3</sub>CN
Bibliographic record
Abstract
A high-yield, high-purity synthesis of (ReO3F)∞ has been achieved by solvolysis of Re2O7 in anhydrous HF (aHF) followed by reaction of the water formed with dissolved F2 at room temperature. The improved synthesis has allowed the Lewis acid and fluoride ion acceptor properties of (ReO3F)∞ to be further investigated. The complex, (HF)2ReO3F·HF, was obtained by dissolution of (ReO3F)∞ in aHF at room temperature and was characterized by vibrational spectroscopy and single-crystal X-ray diffraction at -173 °C. The HF molecules are F-coordinated to rhenium, representing the only known example of a HF complex with rhenium. The trirhenium dianion, [{ReO3(μ-F)}3(μ3-O)](2-), was obtained as the [N(CH3)4](+) salt by the reaction of stoichiometric amounts of (ReO3F)∞ and [N(CH3)4]F in CH3CN solvent at -40 to -20 °C. The anion was structurally characterized in CH3CN solution by (19)F NMR spectroscopy and in the solid state by Raman spectroscopy and a single-crystal X-ray structure determination of [N(CH3)4]2[{ReO3(μ-F)}3(μ3-O)]·CH3CN at -173 °C. The structural parameters and vibrational frequencies of the [{MO3(μ-F)}3(μ3-O)](2-) and [{MO3(μ-F)}3(μ3-F)](-) anions (M = Re, Tc) were calculated using density functional theory. The calculated geometries of [{ReO3(μ-F)}3(μ3-O)](2-) and [{TcO3(μ-F)}3(μ3-F)](-), are in very good agreement with their experimental geometries. Calculated vibrational frequencies and Raman intensities have been used to assign the Raman spectra of (HF)2ReO3F·HF and [N(CH3)4]2[{ReO3(μ-F)}3(μ3-O)]·CH3CN. The X-ray crystal structures of the byproducts, [N(CH3)4][ReO4] and KF·4HF, were also determined in the course of this work.
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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".