Polymer-Free Ethylene Oligomerization Using a Pyridine-Based Pincer PNP-Type of Ligand
Bibliographic record
Abstract
Di- and trivalent chromium complexes of the pyridine-based ligand [2,6-(Ph 2 PCH 2 ) 2 C 5 H 3 N]CrCl 3 ( 1 ) and {[2,6-(Ph 2 CH 2 ) 2 C 5 H 3 N]CrCl 2 }.(THF) ( 2 ) and their aluminate aggregates [2,6-(Ph 2 CH 2 ) 2 C 5 H 3 NCrCl(μ-Cl)AlClMe 2 ] ( 3 ), {[(2,6-(Ph 2 CH 2 ) 2 C 5 H 3 NCrCl(μ-Cl)AlClEt 2 ]}. (toluene) 0.5 ( 4 ), {2,6-(Ph 2 CH 2 ) 2 C 5 H 3 NCrEt(μ-Cl) 2 AlEt 2 }{AlCl 3 Et} ( 5 ), {2,6-(PPh 2 CH 2 ) C 5 H 3 N (PPh 2 CH)Al( i -Bu) 2 (μ-Cl)Cr(μ-Cl) 2 Al( i -Bu) 2 }.(toluene) 1.5 ( 6 ), and {[2,6-(PPh 2 CH 2 ) 2 C 5 H 3 N] 2 Cr} {(μ-Cl)[Al( i -Bu) 3 ] 2 } ( 7 ) were prepared, isolated, and their activities toward ethylene oligomerization tested. While complexes 3, 5, and 6 were directly accessible by reacting catalyst precursor 1 with Me 3 Al, DEAC, and TIBA, respectively, complexes 4 and 7 were prepared using catalyst precursor 2 with DEAC and TIBA, respectively. All these complexes, with the exception of 7, showed good activities for a polymer-free ethylene oligomerization. Complex 7 contains cationic chromium in its monovalent state and its encapsulation in an octahedral ligand field as defined by two ligands is probably responsible for its failure as a catalyst.
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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 | 0.001 |
| 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) | 0.054 | 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".