Controlled Radical Polymerization of Vinyl Acetate with Cyclopentadienyl Chromium β-Diketiminate Complexes: ATRP vs OMRP
Bibliographic record
Abstract
The ability of compounds CpCr II (nacnac Ar,Ar ) (Ar = Dipp, 1; Xyl, 2 ) to catalyze the atom transfer radical polymerization (ATRP) of vinyl acetate has been explored using methyl 2-chloropropionate as initiator. Polymerizations were also carried out under reverse ATRP conditions with thermal initiation by 2,2′-azobis(4-methoxy2,4-dimethylvaleronitrile) (V-70) in the presence of compounds CpCr III (nacnac Ar,Ar )Cl (Ar = Dipp, 3; Xyl, 4 ). All data suggest that these processes are in fact proceeding by organometallic-mediated radical polymerization (OMRP). Stoichiometric reactions between complex 2 and the chlorinated compounds CH 3 CH(Cl)COOCH 3, ClCH 2 COPh, CH 3 CHClOOCCH 3, ClCH 2 OOC t Bu, and ClCH 2 t Bu in the absence of monomer aid in the interpretation of the polymerization results. The first two substrates show rapid one-electron oxidative additions to generate 4 and O-bonded Cr III products, whereas the third and fourth substrates add much more slowly to generate 4 and C-bonded Cr III products; ClCH 2 t Bu does not react. DFT calculations on the competitive radical trapping processes (activation barriers and relative stability of the products) confirm the kinetic and thermodynamic preference for metal−carbon bond formation to generate the dormant species of OMRP.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.063 | 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".