New Pincer-Type Diphosphinito (POCOP) Complexes of Nickel
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Bibliographic record
Abstract
This report describes the synthesis, characterization, and reactivities of a new series of pincer-type nickel complexes based on the diphosphinito (POCOP) ligands 1,3-( i- Pr 2 PO) 2 C 6 H 4, 1, and ( i -Pr 2 POCH 2 ) 2 CH 2, 2 . Reacting these ligands with (THF) 1.5 NiCl 2, (THF) 2 NiBr 2, or (CH 3 CN) n NiX 2 (X = Br, n = 2; I, n = 3) gives pincer-type complexes by metalation of the central carbon atom. The yields of these (POCOP)NiX complexes vary with the type of ligand and Ni precursor used, as well as the reaction conditions. In general, the aromatic ligand 1 was metalated more readily to give excellent yields of the pincer complexes {2,6-( i- Pr 2 PO) 2 C 6 H 3 }NiX (X = Cl, 1a, 85% yield; X = Br, 1b, 95% yield; X = I, 1c, 85% yield), especially when the reaction mixture was heated to 60 °C for 1 h in the presence of 1 equiv of 4-dimethylaminopyridine (DMAP). The analogous reactions of ligand 2 were more sluggish and required refluxing in toluene to give {( i -Pr 2 POCH 2 ) 2 CH}NiX (X = Cl, 2a, 33% yield; X = Br, 2b, 93% yield; X = I, 2c, 70% yield). Displacement of Br from 1b and 2b by Ag(O 3 SCF 3 ), acetonitrile, or acrylonitrile gave, respectively, the neutral Ni−O 3 SCF 3 derivatives 1d and 2d and the cationic adducts of CH 3 CN ( 1e and 2e ) and CH 2 CHCN ( 1f and 2f ). Reacting 1b with MeMgCl or EtMgCl gave the corresponding Ni−alkyl derivatives 1g and 1h, respectively, whereas alkylation of complexes 2a − c was unsuccessful. The POC sp3 OP-based complexes 2a and 2b could be oxidized to paramagnetic, 17-electron species {( i -Pr 2 POCH 2 ) 2 CH}Ni III X 2 (X = Cl, 2i; Br, 2j ). Solid-state structures are reported for Ni−halide derivatives, the neutral complexes 2d, 1g, and 1h, the cationic adduct 1e, and the Ni(III) derivative 2i . The cationic acrylonitrile derivative 1f promotes the Michael addition of morpholine, cyclohexyl amine, or aniline to acrylonitrile, methacrylonitrile, or crotonitrile, whereas the paramagnetic Ni III complex 2j promotes the addition of CCl 4 to methyl acrylate, methyl methacrylate, styrene, 4-methylstyrene, acrolein, and acrylonitrile (Kharasch reaction).
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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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.094 | 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 it