Reactivity Consequences of Steric Reduction in Cyclopentadienyl Chromium β-Diketiminate Complexes
Bibliographic record
Abstract
A series of Cr(III) half-sandwich β-diketiminate complexes, CpCr[(ArNCMe) 2 CH]X, X = I ( 2 ), CH 3 ( 3 ), or Cl ( 4 ), were prepared. Compared to previously communicated complexes with Ar = 2,6- i Pr 2 C 6 H 3 (Dpp, a ), Cr(III) complexes with less sterically demanding ligands such as Ar = 2,6-Me 2 C 6 H 3 (Xyl, b ), 2,4,6-Me 3 C 6 H 2 (Mes, c ), or 2,6-Et 2 C 6 H 3 (Dep, d ) were more readily synthesized via salt metathesis reactions. Iodide compounds 2b − d were prepared by oxidation of the corresponding Cr(II) species CpCr[(ArNCMe) 2 CH] 1b − d with half an equivalent of iodine. The Cr(III) chloride complexes CpCr[(ArNCMe) 2 CH]Cl 4c − d were prepared in a two-step, one-pot reaction from anhydrous CrCl 3 . The reaction of MeMgI with either the Cr(III) chloride or iodide precursors yielded the Cr(III) methyl complexes CpCr[(ArNCMe) 2 CH](CH 3 ) 4b − d . All of the paramagnetic Cr(III) complexes were characterized by UV−visible spectroscopy and elemental analysis, and the structures of 2b, 2c, 3b, 3c, 3d, 4c, and 4d were determined by X-ray crystallography. Reaction of CpCr[(ArNCMe) 2 CH] with iodomethane generates the Cr(III) iodide and Cr(III) methyl complexes. The rate of this single-electron oxidative addition reaction was shown to remain relatively invariant upon changing the β-diketiminate N-aryl substituent.
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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) | 0.012 | 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".