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 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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.023 | 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 teacher head, 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".