[<i>n</i>]Ferrocenophanes (<i>n</i> = 2, 3) with Nitrogen and Phosphorus in Bridging Positions
Bibliographic record
Abstract
The in situ prepared dilithio derivative of the known species 1-bromo-1'-(trimethylsilylamino)ferrocene (1) reacted with tBuPCl2 to form the first example of a [2]ferrocenophane ([2]FCP) bridged by nitrogen and phosphorus (2). Sulfurization of 2 followed by column chromatography on silica gel gave the expected [2]FCP with a tBu(S)PN(SiMe3) bridging moiety (3a) and its desilylated counterpart with a tBu(S)PNH bridging moiety (3b). The molecular structure of 3b was determined by single-crystal X-ray analysis (α = 18.40(11)°). Using a common synthetic methodology, two new 1-amino-1'-bromoferrocene derivatives were prepared, one species with a PhCH2 (6a) and another with a tBuCH2 group (6b) on nitrogen. Dilithiation of 6a followed by addition of tBuPCl2 gave a mixture of three constitutional isomers: the targeted [2]FCP (7a), the 1,1'-disubstituted ferrocene derivative (tBuPH)(PhCH═N)fc (8a), and the [3]FCP bridged by a (NH)(CHPh)PtBu moiety (9a). NMR spectroscopy revealed that 8a is the precursor for 9a. The salt-metathesis reaction of the dilithio derivative of 6b with tBuPCl2 exclusively gave the 1,1'-disubstituted ferrocene derivative (tBuPH)(tBuCH═N)fc (8b), which does not isomerize to the respective [3]FCP. DFT calculations at the M06/6-311+G(d,p) level were used to better rationalize these unexpected results.
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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) | 0.002 | 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".