Promotion of Exocyclic Bond Cleavages in the Decomposition of 1,3-Disilacyclobutane in the Presence of a Metal Filament
Bibliographic record
Abstract
The primary decomposition of 1,3-disilacyclobutane (DSCB) on a tungsten filament and its secondary gas-phase reactions in a hot-wire chemical vapor deposition (CVD) reactor have been studied using laser ionization mass spectrometry. Under the collision-free conditions, DSCB decomposes on the W filament to produce H2 molecules with an activation energy of 43.6 ± 4.1 kJ·mol(-1). With the help of the isotope labeling and chemical trapping methods, the mechanistic details in the secondary gas-phase reactions important in the hot-wire CVD reactor setup have been examined. The dominant pathway has been demonstrated to be the insertion of the cyclic 1,3-disilacyclobut-1-ylidene, generated by exocyclic Si-H bond rupture, into the Si-H bond in DSCB to form 1,1'-bis(1,3-disilacyclobutane) (174 amu). The successful trapping of 1,3-disilacyclobut-1-ylidene by both 1,3-butadiene and trimethylsilane provides compelling evidence for the existence of this cyclic silylene species in the hot-wire CVD reactor with DSCB. Other reactions operating in the reactor include the DSCB cycloreversion to form silene and the ring opening of DSCB via 1,2-H shift to produce silene/methylsilylene and 1-methylsilene/silylene. The introduction of an additional Si atom in the four-membered ring monosilacyclobutane molecule has caused two major changes in the reaction chemistry assumed by DSCB: (1) The endocyclic cycloreversion reactions that dominate in the decomposition of monosilacyclobutane molecules only play a much less important role in the dissociation of DSCB; and (2) the exocyclic bond cleavages are promoted in DSCB due to the ring stabilization caused by the introduction of one additional Si atom.
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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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".