Phosphinimide−Phosphinimide Ligands: New Bulky Ligands for Ethylene Polymerization Catalysts
Bibliographic record
Abstract
The phosphinimide−phosphines PPh 2 (NPR 3 ) (R = i -Pr 1, t- Bu 2 ) were readily prepared in 80−98% yield. These species react with AlMe 3 or B(C 6 F 5 ) 3 to form Me 3 AlPPh 2 (NPR 3 ) (R = i -Pr 3, t- Bu 4 ) and (C 6 F 5 ) 3 B(PPh 2 (NP i -Pr 3 )) ( 5 ), respectively. Oxidation of compounds 1 and 2 with Me 3 SiN 3 yields Me 3 SiNPPh 2 (NPR 3 ) (R = i -Pr 6, t- Bu 7 ). These species react with CpTiCl 3 to give titanium(IV) complexes CpTiCl 2 (NPPh 2 (NPR 3 ) (R = i -Pr 8, t- Bu 9 ) and subsequently the alkylated complexes CpTiMe 2 (NPPh 2 (NPR 3 )) (R = i -Pr 10, t- Bu 11 ). Compounds 8 − 11 were tested for activity in ethylene polymerization. In the presence of excess methylalumoxane, the species 8 and 9 gave rise to active single-site catalysts, generating 299 and 34 gPE mmol - 1 h - 1, respectively. In contrast, activation of 10 and 11 by [Ph 3 C][B(C 6 F 5 ) 4 ] showed negligible polymerization activity. Reaction of 11 with B(C 6 F 5 ) 3 was shown to give numerous products, one of which was the dicationic species [CpTi(μ-Cl)(NPPh 2 (NP t -Bu 3 )] 2 [BC 6 F 5 ) 4 ] 2, 12 . The formation of this species and the implications of these results for catalyst and ancillary ligand design are considered and discussed. X-ray crystallographic data are reported for 1, 3, 4, 8, and 12 .
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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 | 0.001 |
| 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) | 0.021 | 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".