Silica-Grafted Borato Cocatalysts for Olefin Polymerization Modeled by Silsesquioxane−Borato Complexes
Bibliographic record
Abstract
The syntheses and reactivity studies of silsesquioxane−borato complexes are described. Treatment of B(C 6 F 5 ) 3 with (c-C 5 H 9 ) 7 Si 8 O 12 (OH) and (c-C 5 H 9 ) 7 Si 7 O 9 (OH) 3 in the presence of a Brønsted base yields the silsesquioxane−borates X + {[(c-C 5 H 9 ) 7 Si 8 O 13 ]B(C 6 F 5 ) 3 } - ( 1a, X + = PhN(H)Me 2 +; 1b, X + = Et 3 NH + ) and X + {[(c-C 5 H 9 ) 7 Si 7 (OH) 2 O 10 ]B(C 6 F 5 ) 3 } - ( 1b, X + = PhN(H)Me 2 +; 2b, X + = Et 3 NH + ), respectively. When the more nucleophilic base pyridine is used, (C 6 F 5 ) 3 B·NC 5 H 5 ( 3 ) is formed instead, demonstrating the competition between B(C 6 F 5 ) 3 and H + to react with the amine. The dimethylaniline in 1a and 2a is readily exchanged by NEt 3 to form 1b and 2b . With the nucleophilic Lewis base NC 5 H 5, the B−O bond in 1a and 2a is split, yielding (C 6 F 5 ) 3 B·NC 5 H 5 ( 3 ) and the free silsesquioxanes. Complexes 1 and 2 rapidly undergo hydrolysis under formation of the hydroxyl complexes X + {(C 6 F 5 ) 3 BOH} - ( 4a, X + = PhN(H)Me 2 +; 4b, X + = Et 3 NH + ). Likewise, alcoholysis of 1a and 2a with i -PrOH yields the alkoxide {PhN(H)Me 2 } + { i -PrOB(C 6 F 5 ) 3 } - ( 5 ). The B−O bond is only moderately stable toward early-transition-metal alkyls. Nevertheless, Cp 2 Zr(CH 2 Ph) 2 + 1a and Zr(CH 2 Ph) 4 + 2a form single-site ethylene polymerization catalysts. Detailed reactivity studies demonstrated that both B−O and B−C bond splitting plays a crucial role, as not 1a and 2a, but their decomposition product B(C 6 F 5 ) 3 is the actual cocatalyst. The solid-state structures of 1a and 4b were determined by single-crystal X-ray analysis.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.019 | 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".