Yttrium and Aluminum Alkyl Complexes of a Rigid Bis-Anilido NON-Donor Ligand: Synthesis and Hydroamination Catalysis
Bibliographic record
Abstract
The palladium-catalyzed coupling of 4,5-dibromo-2,7-di- tert -butyl-9,9-dimethylxanthene (XBr 2 ) with 2 equiv of 2,4,6-triisopropylaniline afforded the proligand 4,5-bis(2,4,6-triisopropylanilino)-2,7-di- tert -butyl-9,9-dimethylxanthene (H 2 XN 2 ), and reaction of H 2 XN 2 with [Y(CH 2 SiMe 2 R) 3 (THF) 2 ] (R = Me, Ph) produced the monoalkyl yttrium complexes [(XN 2 )Y(CH 2 SiMe 2 R)(THF)] (R = Me ( 1a), Ph ( 1b )). Neutral 1a showed near-zero ethylene polymerization activity (1 atm, 20 and 80 °C), and in the presence of AlMe 3, 1a converted to [(XN 2 )Y{(μ-Me) 2 AlMe 2 }(THF)] ( 2 ). Compound 2 is thermally robust, and transfer of the XN 2 ligand from yttrium to aluminum was not observed even at elevated temperatures. However, [(XN 2 )AlMe] ( 3 ) was accessible via the reaction of H 2 XN 2 with AlMe 3, demonstrating the ability of the wide-bite-angle XN 2 ligand to coordinate to much smaller aluminum(III). Neutral 1a proved to be highly active for both intra- and intermolecular hydroamination with various substrates, yielding Markovnikov products in the intermolecular hydroamination reactions with 1-octene.
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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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".