Electronic Effects in the Oxidative Addition of Iodomethane with Mixed-Aryl β-Diketiminate Chromium Complexes
Bibliographic record
Abstract
The Cr II complexes CpCr[DppNC(Me)CHC(Me)NC 6 H 4 Y] ( 1; Dpp = 2,6-(Me 2 CH) 2 C 6 H 3 ) were used to prepare the corresponding Cr III iodo ( 2 ) and methyl ( 3 ) mixed-aryl β-diketiminate compounds with Y = OMe ( a ), CH 3 ( b ), H ( c ), CF 3 ( d ). Oxidation of the Cr II precursors with iodine gave CpCr[DppNC(Me)CHC(Me)NC 6 H 4 Y](I) ( 2a − d ). The Cr III methyl compounds 3a − d were prepared by reaction of the Cr II complexes with iodomethane followed by MeMgI. The Cr III chloride complexes 4a − d were synthesized by salt metathesis of isolated CpCrCl 2 (THF) with the appropriate deprotonated mixed-aryl β-diketiminate. The structures of the paramagnetic complexes 1b, c, 2a, b, 3a − d, and 4a − d were determined by single-crystal X-ray diffraction. The rate constants for the single-electron oxidative addition of iodomethane with 1a − d were determined by monitoring the reaction by UV−vis spectroscopy. The rate constants correlated well with the electronic parameters of the Y substituents (ρ = −0.36). The rate constants for 1a − d were an order of magnitude greater than those previously obtained for the same reaction with CpCr[(DppNCMe) 2 CH] and related ortho-disubstituted symmetric β-diketiminate complexes.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".