Ruthenated Acetonitrile: Unusual Brønsted Acidity of a Polar “Aprotic” Solvent
Bibliographic record
Abstract
Addition of acetonitrile to the complex [Ru(η 5 -indenyl)(PR 2 )(PPh 3 )] ( 1 ) gives the unusual metalation product [Ru(η 5 -indenyl)(CH 2 CN)(HPR 2 )(PPh 3 )] ( 2 ), which has been structurally characterized. This reaction clearly demonstrates high Brønsted basicity at the terminal phosphido ligand in 1 . 31 P{ 1 H} NMR studies show that less acidic N-donor solvents simply disrupt the Ru−P π-bond in 1 to give adducts [Ru(η 5 -indenyl)(L)(HPR 2 )(PPh 3 )] (L = benzonitrile ( 6 ) or pyridine ( 7 )), which are in equilibrium with 1 and free L. The analogous acetonitrile adduct ( 4 ) was observed by NMR at 240 K during the formation of 2, but is quickly replaced by 2 at higher temperatures. NMR studies of an alternate route to the metalated complex 2, starting from the cationic N-bound acetonitrile adduct [Ru(η 5 -indenyl)(NCCH 3 )(HPCy 2 )(PPh 3 )][PF 6 ] ( 3a ), along with the demonstrated lability of the benzonitrile and pyridine adducts, suggest that the metalation of acetonitrile by 1 proceeds via an intermolecular C−H addition across the Ru═P double bond, rather than the intramolecular C−H activation of N-bound acetonitrile. This is confirmed by the observation, by 31 P{ 1 H} NMR, of multiple product isotopomers in the reaction of 1 with a 1:1 mixture of d 3 - and d 0 -acetonitrile. O-Donor solvents also deprotonated by 1 include water, alcohols, and acetone, which give the complexes [Ru(η 5 -indenyl)(X)(HPCy 2 )(PPh 3 )], where X = OR ( 8 ), CH 2 (═O)CH 3 ( 10 ).
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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".