Synthetic and Computational Studies on the Thermal and Photochemical Reactions of [NPN]TaMe<sub>3</sub> (NPN = PhP(CH<sub>2</sub>SiMe<sub>2</sub>NPh)<sub>2</sub>) and [<sup>Mes</sup>NPN]TaMe<sub>3</sub> (<sup>Mes</sup>NPN = PhP(CH<sub>2</sub>SiMe<sub>2</sub>N(2,4,6-Me<sub>3</sub>C<sub>6</sub>H<sub>2</sub>))<sub>2</sub>)
Bibliographic record
Abstract
The thermolysis of [PhP(CH 2 SiMe 2 NPh) 2 ]TaMe 3 leads to the elimination of methane and the formation of cyclometalated derivative [PhP(CH 2 SiMe 2 NPh)(CH 2 SiMe 2 N- o- C 6 H 4 )]TaMe 2, which was characterized by NMR spectroscopy and single crystal X-ray analysis. Computational studies confirm the expected four-membered transition state involving an ortho - N -phenyl-C–H bond and a Ta-methyl unit. The photolysis of [PhP(CH 2 SiMe 2 NPh) 2 ]TaMe 3 takes a different course; loss of methane also occurs but results in the formation the methylidene complex, [PhP(CH 2 SiMe 2 NPh) 2 ]Ta═CH 2 (Me), which was characterized by NMR spectroscopy. Attempts to block the cyclometalation process by replacement of the N -phenyl substituent with N -Mesityl (Mesityl = 2,4,6-Me 3 C 6 H 2 ) is also reported. With this bulkier ancillary ligand, the reactions are more complicated with multiple products being observed in an overall slow process. The reactions of the trimethyl, the cyclometalated product and the methylidene with H 2 were also investigated and found to exhibit different rates of hydrogenolysis. This has implications for some of the steps in the reaction of [PhP(CH 2 SiMe 2 NPh) 2 ]TaMe 3 with H 2 to generate dinuclear tetrahydride ([PhP(CH 2 SiMe 2 NPh) 2 ]Ta) 2 (μ-H) 4 .
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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 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".