Copper-Catalyzed Bimolecular Coupling of α,ω-Dibromide-Functionalized Poly(γ-caprolactone)
Bibliographic record
Abstract
α,ω-Dibromide-functionalized poly(γ-caprolactone) was synthesized by reacting α,ω-dihydroxy-terminated poly(γ-caprolactone) with an excess of 2-bromoisobutyryl bromide, leading to above 99% esterification. The resulting dibromide end-functionalized polycaprolactone (Br-PCL-Br) was found to “polymerize” in the presence of an excess of copper(I) chloride catalyst without the addition of vinyl monomers. Size exclusion chromatography (SEC) clearly revealed that the molecular weight of the “polymerized” macroinitiator shifts to higher values, and a broad peak was obtained with the main peak centered at a molecular weight which was twice that of the Br-PCL-Br precursor, suggesting that the main reaction is bimolecular coupling (∼80%), while a shoulder at molecular weights about 6−7 times that of the macroinitiator was also observed attributed to multimolecular coupling. The effects of the reaction temperature and the presence of copper(II) catalyst on the radical coupling reactions were also studied. A higher temperature or a lower copper(II) catalyst concentration favored the bimolecular as opposed to the multimolecular coupling, suggesting the possible occurrence of side reactions such as disproportionation and elimination, which hindered further coupling of the free chain ends.
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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".