A new family of monocyclopentadienyl organoscandium <i>bis</i>-alkyls supported by a bulky trialkylphosphine oxide ancillary
Bibliographic record
Abstract
Treatment of the oligomeric compound [Cp*ScCl 2 ] n (Cp* = C 5 Me 5 ) with tri-tert-butylphosphine oxide in THF leads to the monocyclopentadienyl scandium dichloride [Cp*(t-Bu 3 P=O)ScCl 2 ] as a monomeric, THF-free solid in 72% yield. This compound can be alkylated with MeLi to give the corresponding dimethyl derivative, [Cp*(t-Bu 3 P=O)ScMe 2 ], 1. The crystal structures of these two compounds have been done and reveal a three-legged piano stool geometry about the scandium center. The coordinated phosphine oxide ligand exchanges with free donor in both compounds via an associative mechanism, as indicated by the activation parameters (ΔH = 6.48.4 kcal mol 1- ; ΔS = 22.5 to 26.6 eu). Thus, the Cp*(t-Bu 3 P=O) ligand set provides a stable platform for organoscandium chemistry. This was demonstrated by the activation of 1 by treatment with B(C 6 F 5 ) 3 to form the fully characterized contact ion pair [Cp*(t-Bu 3 P=O)ScMe] + [MeB(C 6 F 5 ) 3 ] , 2, which is an active ethylene polymerization catalyst.Key words: organoscandium compounds, olefin polymerization, cationic complexes.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.039 | 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 teacher head, 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".