Inside-protonated 1-azaadamantane: computational studies on the structure, stability, and generation
Bibliographic record
Abstract
Post Hartree–Fock and density functional theory methods have been employed to study inside-protonated 1-azaadamantane 7 and its complexes with the fluoride counterion (contact ion pairs) 10 and 11. The study also involved 1-azaadamantane 4, its outside-protonated form 8, and 1-azaadamantane radical cation 17. Inside-protonated 1-azaadamantane 7 is more than 82 kcal mol−1less stable than out-isomer 8. The repulsive interaction between the internal N+–H group and the azaadamantane cage and a substantial deformation of this cage greatly weaken the C–N and C–C bonds and, consequently, lead to a low kinetic stability of in-ion 7 in the studied unimolecular and bimolecular reactions involving the removal of the encapsulated proton from the cage. Among these reactions, a 7 → 8 rearrangement through a reversible cage opening at the C–N bond was found to be the main transformation channel ([Formula: see text] < 16 kcal mol−1) for in-ion 7. This rearrangement can be catalyzed by an external base, e.g., the fluoride anion. A 1,4-hydrogen migration in 1-azaadamantane radical cation 17 as a possible pathway to the inside-protonated 1-azaadamantane 7 was explored. It was found that this process has a prohibitively high activation barrier, [Formula: see text] > 104 kcal mol−1, and is not able to compete with the α-C–C cleavage of the azaadamantane cage ([Formula: see text] < 26 kcal mol−1).
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".