Synthesis, Characterization, and Oxidation of New POCN<sub>imine</sub>-Type Pincer Complexes of Nickel
Bibliographic record
Abstract
This report describes the synthesis and characterization of new pincer-type complexes of divalent and trivalent nickel. Refluxing toluene mixtures of NiBr 2 (CH 3 CN) n and the unsymmetrical pincer-type ligands Ph-POC H N imine -R gave (Ph-POCN imine -R)Ni(II)Br in good yields (Ph-POC H N imine -R = 1-(Ph 2 PO),3-(CHNR)C 6 H 4; R = Bn, 1; Ph, 2; t -Bu, 3; Cy, 4 ). The C–H nickelation step involved in these syntheses is facilitated in the presence of NEt 3 . Treating compounds 1 – 4 with Br 2, I 2, N -bromosuccinimide (NBS) and N -chlorosuccinimide appears to bring about the desired one-electron oxidation of the Ni(II) center in these complexes, but the putative trivalent species decompose over time and could not be isolated. One of the decomposition products obtained in the Br 2 reaction was identified as the zwitterionic compound [Br 3 Ni(II){κ O -( E )- N -(3-((diphenylphosphoryl)oxy)benzylidene)benzenaminium}], 5 . To identify the factors that are important for isolation of stable trivalent derivatives, we prepared the divalent precursors ( i -Pr-POCN imine -Ph)NiX (X= Br, 6, and NCS, 9 ) and studied their reactions with various oxidants. Whereas treatment of 6 with Br 2 or NBS gave the target 17-electron complex ( i -Pr-POCN imine -Ph)Ni(III)Br 2 ( 7 ), no mixed-ligand trivalent complexes of the type ( i -Pr-POCN imine -Ph)Ni(III)Br(X) could be isolated from reactions of ( i -Pr-POCN imine -Ph)Ni(NCS) ( 9 ) with NBS or of 6 with N -chlorosuccinimide. The latter reaction gave a complex mixture from which was isolated a paramagnetic, trinuclear compound ( 8 ) composed of octahedral Ni(II) units featuring μ 2 -Cl and μ 2,κ O,κ N -succinimide fragments. The solid state structures of all new complexes 2 - 9 have been elucidated by X-ray crystallography.
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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) | 0.007 | 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".