Ruthenium Complexes with Novel Tridentate N<i>,</i>P<i>,</i>N Ligands Containing a Phosphonite Bridge between Two Chiral Oxazolines. Catalytic Activity in Cyclopropanation of Olefins and Transfer Hydrogenation of Acetophenone
Bibliographic record
Abstract
We compare the coordination behavior of the new chiral ligand ( S, S )-bis[1-(4-isopropyl-4,5-dihydrooxazol-2-yl)-1-methylethyl] phenylphosphonite ( V ), abreviated NOPON iPr and referred to as bis(oxazolinyl) phenylphosphonite, toward Ru(II) with that of NOPON Me 2 ( IV ). Although the similarity between IV and V led to the expectation that they would coordinate in a similar manner, considerable differences were observed. Whereas reaction of [RuCl 2 (η 6 - p -cymene)] 2 with IV afforded the pentacoordinated complex [RuCl 2 (NOPON Me 2 )] 1, the chiral ligand V led instead to the dinuclear, chloride-bridged complex [Ru(μ-Cl)Cl(NOPON i Pr )] 2 ( 3 ). The crystal structures of 1 and 3 have been determined by X-ray diffraction. The mer arrangement of the NOPON Me 2 ligand in 1 results from the presence of the four methyl groups, two of which would point toward each other and lead to a steric clash if a fac geometry were adopted. Preliminary theoretical calculations on 1 at the EHT level indicated that coordination of ethylene parallel to the RuCl 2 P plane would result in a stable situation and it is for steric reasons that ethylene does not coordinate to the metal, either parallel or perpendicular to the RuCl 2 P plane. Coordination of CO to 1 was found to be reversible, whereas bulkier ligands do not coordinate to Ru. Complex 3 is a rare example of a fully characterized complex in which a tridentate chiral bis(oxazoline)-type ligand coordinates in a non- mer fashion. It was evaluated in catalytic reactions such as asymmetric cyclopropanation of styrene with ethyl diazoacetate and transfer hydrogenation of acetophenone in propan-2-ol.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.000 | 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".