Pd/X group interchange in the [Pd(Br)(PH<sub>3</sub>)(C<sub>6</sub>H<sub>5</sub>)(C<sub>6</sub>H<sub>5</sub>X)] system — Theoretical insights from the isolobal analogy perspective
Bibliographic record
Abstract
DFT-B3LYP calculations have been carried out to assess the fate of the Pd/X group intermolecular exchange in the [PdBr(PH 3 )(C 6 H 5 )(C 6 H 5 X)] system, where X is either H, an electropositive atom, or a group such as Li, Na, BH 2 , AlH 2 , BeH or BeCH 3 , and an electronegative atom, or a group such as F, Cl, Br, CH 3 , OH, and SH. The transfer of H is best viewed as involving the migration of a proton between the two phenyls. At variance with this result, the transfer of the more electropositive entities such as X = Li, Na, BH 2 , AlH 2 , BeH, or BeCH 3 is not complete. It stops halfway to yield a stable structure in which X can experience interactions with the two phenyl groups that are quite ionic. These stable structures are rationalized through isolobal analogy arguments. In the case of beryllium, the correspondence has been made also with the experimentally known cyclopentadienylberyllium borohydride system, CpBeH 4 . The results of the DFT geometry optimization call for a re-examination of the gas-phase electron-diffraction structure determination, especially for the bond distances and angles that pertain to the two bridging hydrogens. For the halogen series X = F, Cl, or Br and for the electronegative groups CH 3 , OH, or SH, the transfer between the two phenyls takes place via a two-step Pd(II)/Pd(IV) oxidative addition/reductive elimination mechanism. The associated energy barriers are nevertheless quite high, except for Br and SH for which the process might be feasible. The dimerization of the PdBr(PH 3 )(C 6 H 5 ) system is also analyzed within the isolobal analogy framework.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.002 | 0.002 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.003 | 0.000 |
| Research integrity | 0.002 | 0.006 |
| Insufficient payload (model declined to judge) | 0.000 | 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; 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".