(η<sup>5</sup>-Pentamethylcyclopentadienyl)rhodium Complexes of Upper-Rim Monophosphinated Calix[4]arene
Bibliographic record
Abstract
A new and convenient synthesis of the upper-rim monobrominated calix[4]arene Br-calixPR 2 is reported and has been used as the key precursor for the preparation of both the diphenyl- ( 6a ) and diisopropylphosphine ligands ( 6b ). Reactions of these new ligands with [(C 5 Me 5 )RhCl 2 ] 2 afford the complexes (calixPR 2 )(C 5 Me 5 )Rh(Cl) 2 ( 8a, b ), which can be converted into their corresponding dihydrides (calixPR 2 )(C 5 Me 5 )Rh(H) 2 ( 9a, b ) using NaBH 4 . 6a also reacts with (C 5 Me 5 )Rh(CO) 2 to form (calixPPh 2 )(C 5 Me 5 )Rh(CO) ( 10 ). The X-ray structures for both 8a and 8b confirm the cone geometry of the calix[4]arene bowl and reveal the presence of the phenyl and isopropyl groups over the cavity. With respect to the Rh−P bond, a gauche conformation is depicted in the solid state. Complexes 8a, b and 9a, b appear to be fluxional in solution, as demonstrated from VT 1 H and 31 P NMR measurements for 8a, b . Molecular modelings confirm the presence of 13 conformers associated with the rotation around the C(calix)−P and P−Rh bonds and the cavity locking groups above it. The minimum energy conformation for the unsaturated (calixPPh 2 )(C 5 Me 5 )Rh complex exhibits the Rh atom well located at the opening of the free cavity.
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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 | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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".