Dihydrogen Activation by B(<i>p</i>-C<sub>6</sub>F<sub>4</sub>H)<sub>3</sub> and Phosphines
Bibliographic record
Abstract
The Grignard reagent ( p -C 6 F 4 H)MgCl was used to prepare (Et 2 O)B( p -C 6 F 4 H) 3 ( 2 ) and the free borane B( p -C 6 F 4 H) 3 ( 1 ). On the basis of Lewis acidity tests, the borane 1 exhibits ca. 95% of the acidity of B(C 6 F 5 ) 3 . 1 forms classical adducts with ethers and phosphines of the general formula (L)B( p -C 6 F 4 H) 3 (L = Et 2 O ( 2 ), THF ( 3 ), Me 3 P ( 4 ), Et 3 P ( 5 ), i -Pr 2 (H)P ( 6 ), Ph 3 P ( 7 ), (3,5-Me 2 C 6 H 3 ) 3 P ( 8 ), t -Bu 2 (H)P ( 9 ), and Cy 3 P ( 10 )). Compounds 9 and 10 react with 4 atm of H 2 to give the salts [ t -Bu 2 PH 2 ][HB( p -C 6 F 4 H) 3 ] ( 11 ) and [Cy 3 PH][HB( p -C 6 F 4 H) 3 ] ( 12 ). The sterically demanding phosphines R 3 P (R = t -Bu, i -Pr, 2,4,6-Me 3 C 6 H 2, and 2-MeC 6 H 4 ), R 2 R′P (R,R′ = t -Bu, i -Pr and t -Bu, Cy), and (Ph 2 CH)R 2 P (R = t -Bu ( 22 ), i -Pr ( 23 ), Cy ( 24 ), and C 5 H 9 ( 25 )) show no evidence of adduct formation with 1, but react with H 2 to give the corresponding salts [R 3 PH][HB( p -C 6 F 4 H) 3 ] ( 13 − 16 ), [R 2 R′PH][HB( p -C 6 F 4 H) 3 ] ( 17 − 20 ), and [(Ph 2 CH)R 2 PH][HB( p -C 6 F 4 H) 3 ] ( 26 − 29 ), respectively. The [ t -Bu 2 PH 2 ] + species 11 is stable only under an H 2 overpressure, while the [ t -Bu 3 PH] + salt 13 cleanly extrudes isobutene and H 2 at elevated temperatures to give 9 . The [(2-MeC 6 H 4 ) 3 PH] + derivative 16 readily liberates H 2 under vacuum, thus providing a metal-free system capable of reversible H 2 uptake and release. Crystallographic data for compounds 1, 5, 8, 9, 10, 13, and 26 are reported.
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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 | 0.000 |
| 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) | 0.003 | 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; 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".