Phosphinimide complexes with pendant hemilabile donors: synthesis, structure and ethylene polymerization activity
Bibliographic record
Abstract
The phosphines tBu(2)P(CH(2))(3)ECH(2)Ph (E = O (1), S (2)) converted to the corresponding phosphinimines (Me(3)SiN)PtBu(2)(CH(2))(3)ECH(2)Ph, E = O (3), S (4)) which were used to prepared the titanium complexes Cp'TiCl(2)NPtBu(2)(CH(2))(3)ECH(2)Ph, (E = O, Cp' = Cp (5), Cp* (6); E = S, Cp' = Cp (7), Cp* (8)). These species were subsequently methylated to the corresponding dimethyl-derivatives (9)-(12). Activation of (9)-(12) with both B(C(6)F(5))(3) and [Ph(3)C][B(C(6)F(5))(4)] was studied. For example, the [CpTiMe(NPtBu(2)(CH(2))(3)OCH(2)Ph)][MeB(C(6)F(5))(3)] (13) reacted with THF to give [CpTiMe(THF)(NPtBu(2)(CH(2))(3)OCH(2)Ph)][MeB(C(6)F(5))(3)] (14). Similar reactions gave the stable ion pairs [Cp'TiMe(NPtBu(2)(CH(2))(3)XCH(2)Ph)][MeB(C(6)F(5))(3)] (X = O, Cp' = Cp*, (15); X = S Cp' = Cp, (16), Cp*(17)) and [Cp'TiMe(NPtBu(2)(CH(2))(3)XCH(2)Ph)][B(C(6)F(5))(4)] (X = O, Cp' = Cp, (18); Cp*(19); X = S, Cp' = Cp, (20), Cp* (21)). The dihalide complexes (5)-(8), activated with MAO, proved to be ethylene polymerization catalysts of moderate activities. The dialkyl titanium complexes (9)-(12) activated with B(C(6)F(5))(3) or [Ph(3)C][B(C(6)F(5))(4)], gave catalysts that exhibited substantially higher activity and high molecular weight polyethylene. Polymerization at 60 degrees C rather than 30 degrees C significantly increased activity as well. The impact of the hemilabile donor with respect to catalyst activity is discussed. Crystallographic studies of (5) and (6) are reported.
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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) | 0.001 | 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 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".