Factors Influencing the Outcomes of Intermolecular C–H Activations of Hydrocarbons Initiated by CpW(NO)(CH<sub>2</sub>CMe<sub>3</sub>)(η<sup>3</sup>-allyl) Complexes (Cp = η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub> (Cp*), η<sup>5</sup>-C<sub>5</sub>Me<sub>4</sub>H (Cp′))
Bibliographic record
Abstract
Gentle thermolyses of CpW(NO)(CH 2 CMe 3 )(η 3 -allyl) complexes (Cp = η 5 -C 5 Me 5 (Cp*), η 5 -C 5 Me 4 H (Cp′)) in neat hydrocarbon solutions result in the loss of neopentane from the metal’s coordination spheres and the transient formation of the 16-electron (16e) intermediate species CpW(NO)(η 2 -allene) and/or CpW(NO)(η 2 -diene). These transient intermediates can react with hydrocarbon substrates, RH (R = alkyl, aryl), to form three different types of organometallic products. The first products are the desired CpW(NO)(η 3 -allyl)(η 1 -R) complexes that result from the selective single activation of a C–H bond of RH. The second class of products involves CpW(NO)(H)[η 3 -(R)-allyl] complexes that are isomers of the CpW(NO)(η 3 -allyl)(η 1 -R) compounds resulting from an intramolecular R/allyl H exchange. Finally, the third type of products contains CpW(NO)(H)[η 3 -hydrocarbyl] species that result from three successive C–H activations of hydrocarbon substrates such as R′CH 2 CH 2 CH 3 and loss of the original allyl ligand. Just which organometallic products ultimately result from the reactions of the CpW(NO)(CH 2 CMe 3 )(η 3 -allyl) complexes with hydrocarbons depends on several factors, including the natures of the cyclopentadienyl and allyl ligands, the hydrocarbon substrates themselves, the electron density at the metal centers, and the experimental conditions employed. This article documents these dependences and identifies the optimum CpW(NO)(CH 2 CMe 3 )(η 3 -allyl) compounds and experimental conditions for effecting the selective single C–H bond activations of hydrocarbon substrates such as benzene as a representative arene and methylcyclohexane as a representative alkane. During the course of these investigations all new organometallic complexes have been characterized by conventional spectroscopic methods, and the solid-state molecular structures of several of them have been established by single-crystal X-ray crystallographic analyses.
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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) | 0.000 | 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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".