Hyperbranched Polyethylenes Encapsulating Self-Supported Palladium(II) Species as Efficient and Recyclable Catalysts for Heck Reaction
Bibliographic record
Abstract
We demonstrate in this paper a unique self-supporting strategy for the synthesis of hyperbranched polyethylenes (HBPEs) encapsulating Pd(II) species as efficient and recyclable catalysts for Heck reaction. This strategy combines remarkably the synthesis of HBPE polymer support and the immobilization of Pd(II) species in situ in one pot. It is achieved by chain walking copolymerization of ethylene with an acrylate comonomer ( 2 ) containing a disulfide functionality with a cationic Pd(II)–diimine catalyst ( 1 ). The copolymerization renders successfully HBPEs containing pendant disulfide groups at a controllable content, while with no poisoning effect from the disulfide functionality. Meanwhile, the Pd(II) catalyst in situ immobilizes itself onto the polymers by coordinative binding with the pendant disulfide groups, giving rise to the homogeneous self-supported Pd(II) catalysts. The resulting Pd-containing HBPEs having a low content of 2 (ca. < 1 mol %) have been found to be efficient and recyclable catalysts for the Heck reaction of iodobenzene and n -butyl acrylate while with a low/minimum Pd leaching (to form catalytically active species) during the reaction/recycling. In particular, the convenient recovery and reuse of the catalysts while at maintained high catalytic performance has been demonstrated with the use of a biphasic solvent system comprised of N, N -dimethylformamide and n -heptane in the Heck reaction.
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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 | 0.001 | 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) | 0.000 | 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".