Vanadium-Promoted Aldol Condensation and Pinacolic Coupling of Acetylpyrrole: Formation of Two New Potent Dinuclear Catalysts for Olefin Copolymerization
Bibliographic record
Abstract
Reaction of VCl 3 (THF) 3 with 3 equiv of the potassium salt of acetylpyrrole, K[α-(CH 3 CO)C 4 H 3 N], afforded the dinuclear {V 2 [K(THF)] 2 [CH 3 CO(C 4 H 3 N)] 2 }[(C 4 H 3 N)C(O)CH 2 C(C 4 H 3 N)(CH 3 )O] 2 ( 1 ), where four acetylpyrrolide anions from two vanadium moieties have undergone an aldol condensation. The two pyrrolyl−acetylacetonate units so generated work as tetradentate binucleating ligands holding together the dinuclear structure. A similar reaction carried out on the divalent [V 2 Cl 3 (THF) 6 ] 2 [Zn 2 Cl 6 ] salt afforded the dinuclear and trivalent {VK(THF)[(C 4 H 3 N)C(O)CH 3 ]} 2 [(C 4 H 3 N)(CH 3 )(O)CC(O)(CH 3 )(C 4 H 3 N)]·0.5(toluene) ( 2 ), where two acetylpyrrolide ligands, one per vanadium atom, have undergone a reductive coupling to form a pinacol. Even in this case the dipyrrolylpinacol works as a tetradentate binucleating ligand holding together the dinuclear frame. Attempts to perform the same reaction on another V(II) salt such as VCl 2 (TMEDA) 2 (TMEDA = N, N, N ‘, N ‘-tetramethylethylenediamine) afforded instead the corresponding divalent derivative V(TMEDA)[(C 4 H 3 N)C(O)CH 3 ] 2 ( 3 ), where the acetylpyrrolide anions remained intact. Both 1 and 2 are potent olefin copolymerization catalysts upon activation with diethyl aluminum chloride, while 3 displays low but not negligible activity.
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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) | 0.000 | 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) | 0.003 | 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".