Bis(formamidine–urea) Complexes of Ni<sup>II</sup> and Cu<sup>II</sup>:Synthesis, Characterization, and Reactivity
Bibliographic record
Abstract
Abstract A novel chelating chiral bis(formamidine–urea) ligand was synthesized and used to prepare the corresponding Ni II and Cu II complexes. Spectroscopic and X‐ray crystallographic analysis of the former revealed that the urea moiety of the acyclic tetradentate ligand is deprotonated and binds to the square‐planar Ni 2+ ion through amide nitrogen atoms. This complex showed quasi‐reversible redox behavior in cyclic voltammetry, with E 1/2 = 640 mV vs. Cp 2 Fe + /Cp 2 Fe corresponding to the Ni III /Ni II couple. The Cu complex was shown by EPR spectroscopy to also adopt a square‐planar geometry [ g ∥ = 2.25 ( A ∥ = 184 G), g ⟂ = 2.06 at 6 K], and reduction was found to be irreversible, perhaps due to the rigid nature of the tetradentate ligand. The nickel complex was found to be a modestly active catalyst for epoxidation of electron‐richalkenes under Mukaiyama’s conditions, likely involving a radical mechanism. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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) | 0.000 | 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".