Theoretical Study on the Ring-Opening of 1,3-Disilacyclobutane and H<sub>2</sub> Elimination
Bibliographic record
Abstract
The kinetics and thermochemistry of the decomposition pathways for 1,3-disilacyclobutane (1,3-DSCB) in the gas phase were studied using the second-order Møller-Plesset (MP2) perturbation theory and coupled cluster methods with single, double, and perturbative triple excitations (CCSD(T)). The reactions examined include 2 + 2 cycloreversion to form two silenes by either a concerted or a stepwise mechanism, 1,1-, 1,2-, and 1,3-H(2) elimination, and the ring-opening initiated by 1,2-H shift to form an open-chain 1,3-disilabut-1-ylidene, which undergoes further decomposition to produce two pairs of silene/silylene species. The structures of the transition states for the concerted and the stepwise 2 + 2 cycloreversion pathways are found to resemble closely those reported for the head-to-tail and head-to-head dimerization, respectively. Comparison of the activation barriers demonstrates unambiguously that the stepwise cycloreversion (ΔH(0)(‡) = 66.1 kcal/mol) is favored over the concerted one (ΔH(0)(‡) = 77.3 kcal/mol). A new pathway was established from the 1,4-diradical intermediate in the stepwise cycloreversion to form 1-silylmethylsilene via 1,3-H shift. The concerted 1,1-H(2) elimination is shown to have the lowest activation barrier of all H2 elimination reactions. Overall, the 1,2-H shift in 1,3-DSCB with concerted ring-opening to form 1,3-disilabut-1-ylidene is the most kinetically and thermodynamically favorable decomposition pathway, both at 0 and 298 K.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 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".