Observing 2‐vinylpyridine and 4‐vinylpyridine anions during living anionic polymerization by <i>in situ</i> Raman spectroscopy
Bibliographic record
Abstract
We report direct evidence of living anions of 2‐vinylpyridine and 4‐vinylpyridine for the first time to the authors' knowledge on the basis of in situ Raman spectral observations during a living anionic polymerization reaction. The former is characterized by a band at 1607 cm−1 and the latter at 1622 cm−1. A titration experiment was carried out by adding multiple aliquots of 4‐vinylpyridine into a solution containing 2‐vinylpyridine anions. Systematic spectral changes for the aforementioned bands provided convincing evidence for such spectral assignments. These assignments are supported by electronic structure calculations of the monomers and anions. Both anions showed large Raman cross sections, which allowed them to be detected at relatively low concentrations. Such Raman bands will enable facile in situ monitoring of the anionic species and thus can be useful for process development and optimization. Copyright © 2017 John Wiley & Sons, Ltd.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".