Activation and cleavage of alkynes by the dinuclear tantalum complexes ([NPN]Ta)<sub>2</sub>(µ-H)<sub>4</sub> and ([NPN]Ta)<sub>2</sub>(µ-η<sup>1</sup>:η<sup>2</sup>-N<sub>2</sub>)(µ-H)<sub>2</sub> (where NPN = PhP(CH<sub>2</sub>SiMe<sub>2</sub>NPh)<sub>2</sub>)
Bibliographic record
Abstract
Reaction of phenylacetylene with the dinuclear tetrahydride complex ([NPN]Ta) 2 (µ-H) 4 gives the product ([NPN]Ta) 2 (µ-PhCCH)(µ-H) 2 (where NPN is PhP(CH 2 SiMe 2 NPh) 2 ). Activation of other terminal alkynes by ([NPN]Ta) 2 (µ-H) 4 accesses ([NPN]Ta) 2 (µ-RCCH)(µ-H) 2 (R = n-Pr, t-Bu). Crystallographic analysis of the R = Ph derivative showed it to be a bis(µ-alkylidene) bound asymmetrically to the two tantalum centres. Storage of solutions of ([NPN]Ta) 2 (µ-PhCCH)(µ-H) 2 under vacuum promotes the loss of H 2 and cleavage of the CC bond to give a bis(µ-alkylidyne) complex, ([NPN]Ta) 2 (µ-CPh)(µ-CH). Addition of diphenylacetylene did not give the desired ([NPN]Ta) 2 (µ-CPh) 2 , but rather promotes a complex decomposition of the supporting [NPN] ligands. Reaction of phenylacetylene with the dinitrogen complex ([NPN]Ta) 2 (µ-η 1 :η 2 -N 2 )(µ-H) 2 results in the dissociation of the bound dinitrogen and the formation of ([NPN]Ta) 2 (µ-PhCCH)(µ-H) 2 , which is identical to that derived from the reaction with the dinuclear tetrahydride. Key words: tantalum, alkyne, alkylidene, alkylidyne, amidodiphosphine, dinuclear hydride dinitrogen, activation of small molecules.
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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 | 0.005 | 0.003 |
| Meta-epidemiology (narrow) | 0.008 | 0.009 |
| Meta-epidemiology (broad) | 0.009 | 0.005 |
| Bibliometrics | 0.003 | 0.006 |
| Science and technology studies | 0.005 | 0.006 |
| Scholarly communication | 0.003 | 0.005 |
| Open science | 0.007 | 0.002 |
| Research integrity | 0.005 | 0.010 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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; both teacher heads agree on what is shown here.
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".