Dimerization of Ethylene by Palladium Complexes Containing Bidentate Trifluoroborate-Functionalized Phosphine Ligands
Bibliographic record
Abstract
As an alternative to the widely reported phosphine–sulfonate ligand system, a series of potassium aryltrifluoroborate-functionalized phosphine ligands and zwitterionic phosphonium salts were prepared and structurally characterized. The phosphine ligands formed complexes of the general formula [κ 2 -(P,F) R PdClMe] (where R = Ph, 2-OMe-Ph) when reacted with PdClMe(COD); however, cleavage of the chloride ligand proved problematic. Reaction of the phosphonium salts with PdMe 2 (tmeda) yield complexes of the general type [κ-(P) R PdMe(tmeda)], which react with pyridine derivatives to displace tmeda. Manipulation of the steric bulk of the pyridine ligands affords some control over the coordination mode of the fluoroborate phosphine, yielding facile access to complexes of the general type [κ 2 -(P,F) R PdMe(lutidine)]. Investigations into the insertion chemistry of the palladium methyl moiety with simple small molecules revealed that the release of the lutidine ligand is slow and that insertion of ethylene occurs in a very slow manner; this is attributed to the relative electron deficiency of the aryltrifluoroborate moiety as compared to sulfonate. The palladium lutidine complexes slowly dimerize ethylene to a mixture of propene and butenes.
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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".