An Attractive Route to Olefin Metathesis Catalysts: Facile Synthesis of a Ruthenium Alkylidene Complex Containing Labile Phosphane Donors
Bibliographic record
Abstract
Reaction of RuHCl(PPh3)3 4 with 3-chloro-3-methyl-1-butyne effects transformation into RuCl2(PPh3)2(CHCHCMe2) 1c. Starting 4 is available commercially, or via quantitative reaction of RuCl2(PPh3)3 with one equivalent of alkali phenoxides or isopropoxides in refluxing benzene-2-propanol. Phosphane exchange between 1c and PCy3 or 1,3-(CH2PCy2)2C6H4 is rapid at RT, affording RuCl2(PCy3)2(CHCHCMe2) 1b or the novel alkylidene complex RuCl2[1,3-(CH2PCy2)2C6H4](CHCHCMe2) 7. Much slower exchange occurred on use of RuCl2(PCy3)2(CHPh) (1a) as precursor. Complex 1c is stable indefinitely (months) in the solid state at RT under N2, but dimerizes slowly in solution to give RuCl(PPh3)2(μ-Cl)3Ru(PPh3)2(CHCHCMe2) 6a. 2,7-Dimethyl-octa-2,4,6-triene, the formal product of carbene coupling, is observed by 1H NMR. Dimerization does not compete with phosphane exchange. A side-product arising from use of excess 3-chloro-3-methyl-1-butyne in the synthesis of 1c was identified as Ru(IV) carbyne complex RuCl3(PPh3)2(≡CCHCMe2) 5, the structure of which was confirmed by X-ray crystallography.
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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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".