What causes the nonclassical structure of 2-norbornyl ion?
Bibliographic record
Abstract
A recent publication of a general carbocation rearrangement mechanism highlighted protonated cyclopropane (PCP + ) intermediates, whose structures are meso between the nonclassical hypotheses of edge-PCP + and corner-PCP + . Unlike the nonclassical structures, which possess 3-centre–2-electron bonds, the meso-PCP + structures appear as closed classical structures. The 2-norbornyl ion, however, is known to have a nonclassical corner-PCP + structure, and here we explore (using computational chemistry) the reasons why. The main reasons are due to the three 5-membered carbon rings, whose ring strain resist relaxation to a meso-PCP + structure, but an additional reason is the trisubstitution on one side of the PCP + face, which causes unfavourable C–C bond eclipsing.
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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 | 0.001 |
| 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 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".