Theoretical, dynamic, and structural studies of the phenyl rotation in bispentafluorophenyl palladium complexes with scorpion-type ligands
Bibliographic record
Abstract
A theoretical study at a DFT level has been carried out on the pentafluorophenyl rotation in the compounds [Pd(C6F5)2(bpzmPh)] (1) and [Pd(C6F5)2(bpz*mPh)] (2) (bpzm = bis(pyrazol-1-yl)phenylmethane and bpz*mPh = bis(3,5-dimethylpyrazol-1-yl)phenylmethane). The orientation of one C6F5 with respect to the coordination plane was forced to adopt specific values to simulate ring rotation and several parameters, such as the disposition of the other C6F5 group, the energy of the system, and the skeletal conformation of the bpz'm ligand, were analysed. The maximum energy value was found when the C6F5 ring was nearly coplanar with the coordination plane. In both complexes the minimum energy corresponds to a situation where the two rings are nearly parallel. A number of distortions that mainly affect the NPdN bite angle were predicted for the complex containing the bpz*mPh ligand (methylated pyrazoles). Four structures of complexes from this family were determined by X-ray diffraction and the same types of distortion were found. The differences in the free energies of activation for the pentafluorophenyl rotation in complexes containing methylated and non-methylated ligands were theoretically calculated. The calculated values were consistent with the data experimentally determined by NMR spectroscopy. The origin of the difference was attributed to the aforementioned distortions of the complexes containing the bpz*mPh ligand, which were more remarkable in the configuration of maximum energy.Key words: N ligands, palladium, theoretical studies, DFT calculations, dynamics.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.005 | 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".