The fluxionality and crystal structures of [Fe<sub>3</sub>(CO)<sub>10</sub>L<sub>2</sub>] (L<sub>2</sub> = dppm, (Ph<sub>2</sub>P)<sub>2</sub>NH, {(EtO)<sub>2</sub>P}<sub>2</sub>O) and [Fe<sub>3</sub>(CO)<sub>9</sub>(dppm){P(OMe)<sub>3</sub>}]
Bibliographic record
Abstract
The crystal structures of [Fe 3 (CO) 10 L 2 ] (L 2 = dppm, (Ph 2 P) 2 NH, {(EtO) 2 P} 2 O) and [Fe 3 (CO) 9 (dppm){P(OMe) 3 }] (dppm = (Ph 2 P) 2 CH 2 ) have been determined. [Fe 3 (CO) 10 L 2 ] (L 2 = dppm, (Ph 2 P) 2 NH, {(EtO) 2 P} 2 O) adopt a stereochemistry in the crystal with the bidentate ligand across an unbridged Fe-Fe edge, resulting in one phosphorus ligand being unusually in the axial position. In contrast, [Fe 3 (CO) 9 (dppm){P(OMe) 3 }] adopts a stereochemistry in the crystal with the bidentate ligand across the bridged Fe-Fe edge. The structures of the [Fe 3 (CO) 10 L 2 ] (L 2 = dppm, (Ph 2 P) 2 NH, {(EtO) 2 P} 2 O) support the Mann concerted bridge - opening bridge - closing mechanism of carbonyl fluxionality rather than the Johnson libration mechanism. The fluxionality of the compounds in the 13 C NMR spectra is explained by a combination of the concerted bridge - opening bridge - closing, merry-go-round, and trigonal twist mechanisms, and ΔG values were determined.Key words: iron carbonyls, crystal structures, 13 C NMR spectroscopy, fluxionality, mechanisms.
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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 | 0.014 | 0.008 |
| Meta-epidemiology (narrow) | 0.013 | 0.015 |
| Meta-epidemiology (broad) | 0.013 | 0.007 |
| Bibliometrics | 0.007 | 0.010 |
| Science and technology studies | 0.010 | 0.013 |
| Scholarly communication | 0.008 | 0.009 |
| Open science | 0.013 | 0.004 |
| Research integrity | 0.009 | 0.014 |
| Insufficient payload (model declined to judge) | 0.001 | 0.002 |
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; both teacher heads agree on what is shown here.
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".