Extremely Facile Transformations of Tris(3,5‐dimethylpyrazolyl)borate: a Bidentate Nitrogen Ligand and a <i>C</i><sub>2</sub>‐Chiral Cation
Bibliographic record
Abstract
Abstract Two novel transformations are reported for the well‐known hydridotris(3,5‐dimethylpyrazolyl)borate (Tp*–). The uncommon Lewis base abstractor aryldiazonium cation (ArN2+; Ar = p‐Br‐C6H4, p‐MeO‐C6H4) if used in equimolar amounts, removes a hydride from Tp*– in acetone to produce the formal acetone adduct of tris(3,5‐dimethylpyrazolyl)borane (pz*3B·C3H6O, compound 1). Frustrated Lewis pair (FLP) like behavior is thus found for a tris(pyrazolyl)borane. If 2 equiv. of ArN2+ are used, 3,5‐dimethylpyrazolate is now being abstracted from 1, and the resulting intermediate bifunctional borane adds another equivalent of acetone to form cation 2+ {[pz*2B·(C3H6O)2]+, obtained as 2‐BF4}, a boronium cation that is the formal addition product of 2 equiv. of acetone to the bis(3,5‐dimethylpyrazolyl)borinium cation. Compounds 1 and 2+ are characterized by 1H, 13C, and 11B NMR spectroscopy, mass spectrometry, and single‐crystal X‐ray diffraction. Compound 1 is potentially useful as a charge‐neutral bidentate chelate ligand with controlled sterics, and 2+ is a C2‐chiral cation.
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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) | 0.002 | 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 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".