Isomerization of an Enantiomerically Pure Phosphorus-Bridged [1]Ferrocenophane
Bibliographic record
Abstract
The enantiomerically pure phospha[1]ferrocenophane 4- C 1 was prepared through a salt-metathesis reaction between t BuPCl 2 and a chiral dilithioferrocene derivative (Li 2 fc 3-Pen ), which was equipped with two 3-pentyl groups in α positions with respect to lithium on the Cp rings ( S p,S p isomer; C 2 symmetry). The chiral 4- C 1 isomerizes in reaction mixtures to give the C s -symmetrical phospha[1]ferrocenophane 4- C s . This thermal isomerization involves haptotropic η 5 to η 1 shifts of Cp rings and is catalyzed by the chelating ligand 1,1′-( t BuClP) 2 fc 3-Pen, which is a byproduct of the salt-metathesis reaction. Both phospha[1]ferrocenophanes, 4- C 1 and 4- C s, were isolated and characterized as pure compounds; the molecular structure of 4- C s was determined by a single-crystal X-ray analysis. According to DFT calculations, the equilibrium constant K ° for 4- C 1 ⇌ 4- C s is 4.43 (Δ E SCF = −3.74 kcal/mol; Δ H ° = −3.81 kcal/mol; Δ G ° = −3.68 kcal/mol). As deduced from calculated molecular geometries, the thermodynamic difference between both isomers is mainly caused by a steric repulsion between the t Bu group on phosphorus and one of the 3-pentyl groups on a Cp ring in the isomer 4- C 1 .
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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 | 0.000 |
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".