Chalcogen versus Dative Bonding in [SF<sub>3</sub>]<sup>+</sup> Lewis Acid–Base Adducts: [SF<sub>3</sub>(NCCH<sub>3</sub>)<sub>2</sub>]<sup>+</sup>, [SF<sub>3</sub>(NC<sub>5</sub>H<sub>5</sub>)<sub>2</sub>]<sup>+</sup>, and [SF<sub>3</sub>(phen)]<sup>+</sup> (phen = 1,10-phenanthroline)
Bibliographic record
Abstract
The Lewis-acid behavior of [SF3][MF6] (M = Sb, As) salts toward mono- and bidentate nitrogen bases was explored. Reactions of [SF3][MF6] with excesses of CH3CN and C5H5N yielded [SF3(L)2]+ (L = CH3CN, C5H5N) salts, whereas the reaction of [SF3][SbF6] with equimolar 1,10-phenanthroline (phen) in CH3CN afforded [SF3(phen)][SbF6]·2CH3CN. Salts of these cations were characterized by low-temperature X-ray crystallography and Raman spectroscopy in the solid state as well as by 19F NMR spectroscopy in solution. In the solid state, the geometries of [SF3(NC5H5)2]+ and [SF3(phen)]+ are square pyramids with negligible cation–anion contacts, whereas the coordination of CH3CN and [SbF6]− to [SF3]+ in [SF3(NCCH3)2][SbF6] results in a distorted octahedral coordination sphere with a minimal perturbation of the trigonal-pyramidal SF3 moiety. 19F NMR spectroscopy revealed that [SF3(L)2]+ is fluxional in excess L at −30 °C, whereas [SF3(phen)]+ is rigid in CH2Cl2 at −40 °C. Density functional theory (DFT-B3LYP) calculations suggest that the S–N bonds in [SF3(NC5H5)2]+ and [SF3(phen)]+ possess substantial covalent character and result in a regular AX5E VSEPR geometry, whereas those in [SF3(NCCH3)2]+ are best described as S···N chalcogen-bonding interactions via σ-holes on [SF3]+, which is consistent with the crystallographic data.
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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 | 0.009 | 0.009 |
| Meta-epidemiology (narrow) | 0.021 | 0.025 |
| Meta-epidemiology (broad) | 0.018 | 0.009 |
| Bibliometrics | 0.005 | 0.018 |
| Science and technology studies | 0.009 | 0.009 |
| Scholarly communication | 0.006 | 0.009 |
| Open science | 0.015 | 0.014 |
| Research integrity | 0.018 | 0.026 |
| Insufficient payload (model declined to judge) | 0.001 | 0.008 |
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".