Protonated silanoic acid HSi(OH)<sub>2</sub><sup>+</sup> and its neutral counterpart: a tandem mass spectrometric and CBS‐QB3 computational study
Bibliographic record
Abstract
Abstract Protonated silanoic acid, HSi(OH) 2 + , 1a + , is cleanly generated by the dissociative electron ionization of triethoxysilane, HSi(OC 2 H 5 ) 3 , and tetraethoxysilane, Si(OC 2 H 5 ) 4 . This follows from tandem mass spectrometric experiments and CBS‐QB3 model chemistry calculations. The calculations predict that 1a + (Δ H f (298 K) = 205 kJ mol −1 ) is separated by high barriers from its isomers HOSiOH 2 + , 1b + and HSi(O)OH 2 + , 1c + . Low‐energy (metastable) ions 1a + dissociate by loss of H 2 O via the pathway 1a + → 1b + → SiOH + + H 2 O. Analysis of the metastable peak for this process confirms that the isomerization step 1a + → 1b + is rate determining. The calculations further predict that the incipient ions 1b + communicate via a low barrier with the proton‐bound dimer SiO···H···OH 2 + , 1d + . This dimer ion is much lower in energy than its counterpart OSi···H···OH 2 + , 1e + , which is calculated to be only marginally stable. A comparison of the potential energy diagram for the silicon‐containing ions 1a + – 1e + with that of their carbon analogues reveals that the dissociation chemistries of HSi(OH) 2 + and HC(OH) 2 + are only superficially similar. Neutralization–reionization experiments confirm the theoretical prediction that the HSi(OH) 2 • radical (Δ H f (298 K) = −455 kJ mol −1 ) is a stable species in the rarefied gas phase. However, owing to a mismatch of Franck–Condon factors a large fraction of the neutralized ions dissociates by loss of H • yielding Si(OH) 2 . Copyright © 2004 John Wiley & Sons, Ltd.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".