The Syntheses of Carbocations by Use of the Noble-Gas Oxidant, [XeOTeF<sub>5</sub>][Sb(OTeF<sub>5</sub>)<sub>6</sub>]: The Syntheses and Characterization of the CX<sub>3</sub><sup>+</sup> (X = Cl, Br, OTeF<sub>5</sub>) and CBr(OTeF<sub>5</sub>)<sub>2</sub><sup>+</sup> Cations and Theoretical Studies of CX<sub>3</sub><sup>+</sup> and BX<sub>3</sub> (X = F, Cl, Br, I, OTeF<sub>5</sub>)
Bibliographic record
Abstract
The CCl(3)(+) and CBr(3)(+) cations have been synthesized by oxidation of a halide ligand of CCl(4) and CBr(4) at -78 degrees C in SO(2)ClF solvent by use of [XeOTeF(5)][Sb(OTeF(5))(6)]. The CBr(3)(+) cation reacts further with BrOTeF(5) to give CBr(OTeF(5))(2)(+), C(OTeF(5))(3)(+), and Br(2). The [XeOTeF(5)][Sb(OTeF(5))(6)] salt was also found to react with BrOTeF(5) in SO(2)ClF solvent at -78 degrees C to give the Br(OTeF(5))(2)(+) cation. The CCl(3)(+), CBr(3)(+), CBr(OTeF(5))(2)(+), C(OTeF(5))(3)(+), and Br(OTeF(5))(2)(+) cations and C(OTeF(5))(4) have been characterized in SO(2)ClF solution by (13)C and/or (19)F NMR spectroscopy at -78 degrees C. The X-ray crystal structures of the CCl(3)(+), CBr(3)(+), and C(OTeF(5))(3)(+) cations have been determined in [CCl(3)][Sb(OTeF(5))(6)], [CBr(3)][Sb(OTeF(5))(6)].SO(2)ClF, and [C(OTeF(5))(3)][Sb(OTeF(5))(6)].3SO(2)ClF at -173 degrees C. The CCl(3)(+) and CBr(3)(+) salts were stable at room temperature, whereas the CBr(n)(OTeF(5))(3-n)(+) salts were stable at 0 degrees C for several hours. The cations were found to be trigonal planar about carbon, with the CCl(3)(+) and CBr(3)(+) cations showing no significant interactions between their carbon atoms and the fluorine atoms of the Sb(OTeF(5))(6)(-) anions. In contrast, the C(OTeF(5))(3)(+) cation interacts with an oxygen of each of two SO(2)ClF molecules by coordination along the three-fold axis of the cation. The solid-state Raman spectra of the Sb(OTeF(5))(6)(-) salts of CCl(3)(+) and CBr(3)(+) have been obtained and assigned with the aid of electronic structure calculations. The CCl(3)(+) cation displays a well-resolved (35)Cl/(37)Cl isotopic pattern for the symmetric CCl(3) stretch. The energy-minimized geometries, natural charges, and natural bond orders of the CCl(3)(+), CBr(3)(+), CI(3)(+), and C(OTeF(5))(3)(+) cations and of the presently unknown CF(3)(+) cation have been calculated using HF and MP2 methods have been compared with those of the isoelectronic BX(3) molecules (X = F, Cl, Br, I, and OTeF(5)). The (13)C and (11)B chemical shifts for CX(3)(+) (X = Cl, Br, I) and BX(3) (X = F, Cl, Br, I) were calculated by the GIAO method, and their trends were assessed in terms of paramagnetic contributions and spin-orbit coupling.
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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".