Insight into the Formation of Highly Strained [1]Ferrocenophanes with Boron in Bridging Position
Bibliographic record
Abstract
Four planar-chiral, enantiomerically pure ferrocene dibromides ( 3 R1R2; [(CHR 1 R 2 )BrH 3 C 5 ] 2 Fe) equipped with two CHR 1 R 2 groups in α position to bromine were synthesized. From the four C 2 symmetrical species, two are already known [CHR 1 R 2 = CHMe 2 ( 3 MeMe ), CHEt 2 ( 3 EtEt )] and two are new compounds [CHR 1 R 2 = R -CHEtMe ( 3 EtMe ), S -CHMeEt ( 3 MeEt )]. The dibromides 3 R1R2 were in situ converted into dilithio ferrocene derivatives and reacted with Cl 2 BN i Pr 2 resulting in mixtures of bora[1]ferrocenophanes ( 4 R1R2 ) and 1,1′-bis(boryl)ferrocenes ( 5 R1R2 ). The aim of this investigation was to test the hypothesis that the alkyl group that is oriented approximately perpendicular to the Cp ring, i.e., R 2, affects the outcome of the salt-metathesis reaction. The obtained product ratios 4 R1R2: 5 R1R2 were determined by 1 H NMR spectroscopy and revealed that systems with the same R 2 group gave similar 4 R1R2: 5 R1R2 ratios (1.0:0.51 and 1.0:0.49 for R 2 = Me; 1.0:0.30 and 1.0:0.27 for R 2 = Et), confirming the hypothesis. Shown by DFT calculations (B3PW91/6-311+G(d,p)), reaction paths resulting in either product 4 R1R2 or product 5 R1R2 are both concerted steps.
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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) | 0.001 | 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".