Chain‐Conformation‐Directed Polymerization Cyclization for Effective Synthesis of Macrocycles in Bulk
Bibliographic record
Abstract
Abstract Biological cyclization is highly efficient, and this can be attributed to the conformation of the backbone of the biopolymer. Taking advantage of metal‐coordination geometry, we developed a method for conformation‐directed polymerization cyclization through rational design of metal carbonyl monomers that could be used to produce cyclic macromolecules, even in bulk. PFpR [PFp=(PPh2(CH2)3Cp)Fe(CO)2 with the phosphine group tethered on the cyclopentadiene (Cp) ring; R=CH3 or (CH2)5CH3] was designed and synthesized for migration insertion polymerization to generate P(PFpR) with the polymer backbone containing Cp−Fe bonds. Growth of the backbone led to a cyclic conformation with close end‐to‐end distances, which facilitated the cyclization. This conformation‐directed cyclization was attributed to the piano‐stool metal‐coordination geometry of the repeating units and the low rotational barrier of the Cp−Fe bonds in the backbone. The produced macrocycles, which contain a metal carbonyl coordination structure in their backbones, are rigid, unlike many organic macrocycles. The macrocycles thus have a large excluded volume. This new type of metal carbonyl macrocycle will be of interest as a building block for supramolecular chemistry and in the exploration of novel materials.
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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) | 0.002 | 0.001 |
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".