Oxygen Atom Transfer to Cationic PCPNi(II) Complexes Using Amine-<i>N</i>-Oxides
Bibliographic record
Abstract
Three PC sp3 P pincer ligands differing in the aryl group linking the phosphine arms with the anchoring carbon donor were used to support square planar Ni(II) bromide complexes 1 – 3 Br . Exchange of the coordinating bromide anion for the more weakly coordinating triflate (OTf) or hexafluoroantimonate (SbF 6 ) anions was accomplished by treatment with AgX or TlX salts to give compounds 1 – 3 X; compounds 1 OTf, 1 SbF 6, 2 Br, 2 OTf, 3 Br, and 3 SbF 6 were all characterized by X-ray crystallography. The reactions of these Ni(II) compounds with the amine- N -oxide oxygen atom transfer agents ONMe 3 and ONMePh 2 were explored. For ONMe 3, reactions with 2 equiv gave products in which one arm of the pincer ligand was oxidized to a P═O unit, with the other amine- N -oxide ligated to the Ni(II) center, forming products 5 – 6 X; compounds 4 OTf, 5 OTf, and 6 SbF 6 were characterized crystallographically. Transient amine- N -oxide adducts prior to ligand oxidation were observed in some reactions. For the more effective O atom donor ONMePh 2, reactions were very rapid and a second oxidation of the remaining phosphine arm was observed, producing a Ni(II) species with an OCO pincer ligand ( 7 SbF 6 ). All compounds were fully characterized. Experiments aimed at trapping transient Ni(IV) oxo intermediates (with cyclohexadiene, KH, and various Lewis acids) indicated that such species were not involved in the reaction. This was supported by density functional theory (DFT) computations at the B3PW91 level, which indicated that direct O atom insertion into the Ni–P bonds without the intermediacy of a Ni oxo species was the low-energy pathway.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.007 | 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".