Three Products Are Better than Two: Entropic Advantages in the Competing Dissociation Reactions of Ionized Azo-<i>t</i>-butane
Bibliographic record
Abstract
Ionized azo-t-butane (m/z 142) undergoes three dissociation reactions: competitive cleavage of the N-C bond to form (1) the t-butyl cation ((CH(3))(3)C(+), m/z 57) plus a neutral that is nominally (CH(3))(3)CN(2)(*) (85 Da); (2) m/z 85 cation, (CH(3))(3)CN(2)(+), plus the neutral t-butyl radical; and (3) a minor rearrangement reaction leading to ionized butene. The competition between channels (1) and (2) is governed by both energetic and entropic considerations as the 85 Da neutral lies in a 1 kJ mol(-1) potential energy well and when formed dissociates into the t-butyl radical and N(2). This gives channel 1 an entropic advantage over channel 2, as long as the transition states for these processes reside close to products, a conclusion supported by threshold photoelectron photoion coincidence spectroscopy, tandem mass spectrometry, and ab initio calculations.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.007 | 0.001 |
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".