Chromium Amino-bis(phenolate) Complexes as Catalysts for Ring-Opening Polymerization of Cyclohexene Oxide
Bibliographic record
Abstract
The chromium(III) amino-bis(phenolate) “ate” complex, {Na[CrCl 2 L1 ]}, 1, where L1 = 6,6′-((1,4-diazepane-1,4-diyl)bis(methylene))bis(2,4-di- tert -butylphenolato) and its derivatives 2 – 4 (where the phenolate substituents and the diamino linker were varied) were prepared. Single crystals obtained by recrystallization of 1 were shown by X-ray diffraction to be a related octahedral complex, 1′, where one of the O-donors in 1′ is protonated, resulting in a monoanionic ligand and affording a neutral Cr(III) dichloride complex. The ligand [ L1 ] chelates in a meridional fashion and anionic chloride donors reside in a trans axial orientation. Cr(III) amino-bis(phenolate) complexes 1 – 4 showed good activity toward ring-opening polymerization (ROP) of cyclohexene oxide (CHO) without the use of an added cocatalyst, producing high-molecular weight poly(cyclohexene oxide) where 1 was the most active catalyst. Arrhenius data obtained for the ROP of CHO using 1 revealed an activation barrier of 64.0 ± 9.8 kJ mol –1 and the nonlinear polymer molecular weight growth versus conversion relationship suggests a step-growth polymerization mechanism.
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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".