Creating Three Pentacoordinated Carbons in a Six-Membered Ring. An Atoms-in-Molecules and Electron-Localization Function Study on the Trishomocyclopropenyl Cation and Phosphorus, Sulfur, Arsenic, and Selenium Analogues
Bibliographic record
Abstract
The trishomocyclopropenyl cation and related species were investigated at the Becke3PW91/6-311G(d,p) and MP4(SDQ)/6-311G(d,p) levels of theory. The bonding was characterized on the basis of atoms-in-molecules (AIM) theory, as well as in terms of basins and their populations within the electron-localization function (ELF) framework. There are no pentacoordinated carbons in the trishomocyclopropenyl cation, although it is stabilized by σ,σ-no-bond homoconjugation; it is not a hypercoordinate species. Only when the C1−C3, C3−C5, and C1−C5 distances are fixed at 1.576 Å is a σ,σ-bond homoconjugated species obtained, but it is not a stationary point and is 21.7 kcal mol -1 higher in energy than the equilibrium-optimized trishomocyclopropenyl cation. When the methylene groups of the trishomocyclopropenyl cation are replaced with PH, S, AsH, and Se, equilibrium-optimized σ,σ-bond homoconjugated species that exhibit three pentacoordinated carbons are obtained. A rationale for these observations is presented.
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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 | 0.001 | 0.001 |
| 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 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".