Intermolecular Activation of Hydrocarbon C−H Bonds Initiated by the Tungsten Hydrocarbyl Hydrido Complexes Cp*W(NO)(R)(H)(PMe<sub>3</sub>) (R = Alkyl, Aryl)
Bibliographic record
Abstract
trans -Cp*W(NO)(CH 2 EMe 3 )(H)(PMe 3 ) (E = C, Si) complexes can be prepared by the hydrogenation at 1 atm of the appropriate Cp*W(NO)(CH 2 EMe 3 ) 2 precursor in the presence of a slight excess of PMe 3 . (Our designation of a particular geometrical isomer as cis or trans in this family of complexes indicates the relative positions of the hydrocarbyl and the hydrido ligands in the base of a four-legged piano-stool molecular structure.) The use of D 2 in place of H 2 during these syntheses affords the corresponding trans -Cp*W(NO)(CH 2 EMe 3 )(D)(PMe 3 ) (E = C, Si) complexes. The cis -Cp*W(NO)(CH 2 EMe 3 )(H)(PMe 3 ) isomers are obtainable by C−H bond-activation reactions of the trans precursors. Thus, activation of SiMe 4 by trans -Cp*W(NO)(CH 2 CMe 3 )(H)(PMe 3 ) under ambient conditions produces cis -Cp*W(NO)(CH 2 SiMe 3 )(H)(PMe 3 ). Similarly, activations of C 6 H 6 and C 6 D 6 at 20−27 °C by the trans -Cp*W(NO)(CH 2 EMe 3 )(H)(PMe 3 ) complexes produce cis -Cp*W(NO)(C 6 H 5 )(H)(PMe 3 ) and cis -Cp*W(NO)(C 6 D 5 )(D)(PMe 3 ), respectively, and the solid-state molecular structure of the latter complex has been established by a single-crystal X-ray crystallographic analysis. Kinetic, mechanistic, and theoretical investigations of these benzene C−H activation processes are consistent with initial trans to cis isomerization of the reactants followed by intramolecular reductive elimination of EMe 4 to form the 16-electron Cp*W(NO)(PMe 3 ) intermediate. Subsequent oxidative addition of the incoming benzene substrate to this coordinatively unsaturated intermediate produces the final cis hydrido phenyl complex. These single C−H activation processes are the requisite first steps in the development of these organometallic complexes as catalysts for the selective functionalization of hydrocarbons. All new complexes have been characterized by conventional spectroscopic methods.
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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) | 0.001 | 0.001 |
| 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 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".