The Effects of Activators on Zirconium Phosphinimide Ethylene Polymerization Catalysts
Bibliographic record
Abstract
Synthetic routes to the species CpZr(NP t- Bu 3 ) 2 Cl, 7, Cp 2 Zr(NP t- Bu 3 )Cl, 8, CpZr(NP t -Bu 3 ) 2 Me, 9, Cp 2 Zr(NP t- Bu 3 )Me, 10, and CpZr(NP t -Bu 3 ) 2 Bn, 11, were developed in a manner similar to that previously reported for zirconium phosphinimide complexes. Rather than employing metathesis routes, transamination was considered to synthesize bis-phosphinimide zirconium complexes. At ambient temperature, Zr(NP t -Bu 3 ) 3 (NMe 2 ), 15, was isolated in less than 5% yield, but could be obtained cleanly via reaction of Zr(NP t -Bu 3 ) 3 Cl, 14, with LiNMe 2 . However, thermolysis of Zr(NEt 2 ) 4 with HNP t -Bu 3 afforded Zr(NP t -Bu 3 ) 2 (NEt 2 ) 2, 12, which was subsequently converted to Zr(NP t -Bu 3 ) 2 Cl 2, 13, upon reaction with trimethylsilyl chloride. Cationic products were generated from the reaction of Lewis acids in the presence of a donor to provide the salts [CpZr(NP t -Bu 3 )Me(THF)][MeB(C 6 F 5 ) 3 ], 16, [Cp*Zr(NP t- Bu 3 )(( i -PrN) 2 CMe)][MeB(C 6 F 5 ) 3 ], 17, and [CpZr(NP t- Bu 3 )(( i -PrN) 2 CMe)][MeB(C 6 F 5 ) 3 ], 18 . Similarly, reaction of [HNMe 2 Ph][B(C 6 F 5 ) 4 ] with 4 generated the salt [CpZr(NP t -Bu 3 )Me(NMe 2 Ph)][B(C 6 F 5 ) 4 ], 19, while reaction of 11 with B(C 6 F 5 ) 3 gave the base-free product [CpZr(NP t -Bu 3 ) 2 ][BnB(C 6 F 5 ) 3 ], 20 . Structural considerations and preliminary MO calculations support the reactivity studies that augur well for olefin polymerization activity. Experimentally, previously reported screening using MAO as a solvent scrubber/activator with 1 − 4 showed only moderate polymerization activities. However, use of 20 equiv of Al( i -Bu) 3 as scavenger and 2 equiv of B(C 6 F 5 ) 3 as cocatalyst resulted in a significant increase in activity relative to that observed upon activation with MAO. Use of [Ph 3 C][B(C 6 F 5 ) 4 ] as the cocatalyst led to even higher ethylene polymerization activities.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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) | 0.001 | 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 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".