An Ultrafast Benchmark for Ring Opening Metathesis Polymerization Catalysts: A Ruthenium Phosphinimine System Approaching the Diffusion Rate Limit
Bibliographic record
Abstract
A ruthenium phenylidene complex bearing a monodentate phosphinimine ligand ( Ru1 ) was investigated as a ring-opening metathesis polymerization (ROMP) catalyst. Building on prior studies showing ultrafast initiation and a bimolecular mechanism of decomposition, Ru1 was evaluated using norbornene (NBE), cyclooctene (COE), and cyclooctadiene (COD) as model substrates. Kinetic analysis revealed first-order dependence on monomer concentration, consistent with catalyst activation proceeding through a rate-limiting interchange ligand substitution reaction. Ru1 displayed exceptional activity, achieving turnover frequencies (TOFs) up to 4.00 × 10 4 s –1 and turnover numbers (TONs) up to 232,000 for NBE, TOFs up to 9.88 × 10 3 s –1 and TONs up to 240,000 for COE, and TOFs up to 1.80 × 10 2 s –1 with TONs up to 2760 for COD. Experimentally determined rate constants reached 7.9 × 10 8 M –1 ·s –1 (NBE), 9.6 × 10 7 M –1 ·s –1 (COE), and 1.1 × 10 5 M –1 ·s –1 (COD); values that approach the diffusion limit and rival the fastest enzymatic systems. To the best of our knowledge, these are the highest catalytic rates reported for ROMP to date, establishing Ru1 as a benchmark system for ultrafast metathesis polymerization.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".