The Effect of Phenyl Substitution on the Thermochemistry of Gas-Phase Ions and Their Neutral Counterparts
Bibliographic record
Abstract
The available data for the heats of formation of phenyl-substituted organics have been critically evaluated. Phenyl substitution is always thermochemically destabilizing in that Δ f H 0 [R–C 6 H 5 ] – Δ f H 0 [R–H] is a positive quantity. The magnitude of the effect in neutrals depends on the substitution site, e.g. from + 79 kJ mol −1 for HCOR or HCCR to + 155 kJ mol −1 for RCO 2 H. Multiple phenyl substitution (where possible) at the same site is generally simply additive. For the corresponding cationic species, the first phenyl substitution is stabilizing when the ionization energy of the substrate is lowered thereby and for even-electron ions resonance-stabilization energies may also come into play. Additional phenyl substitution at the same site is, however, always destabilizing. Phenyl substitutions were compared with vinyl substitution: for neutral species the effects are similar, whereas for even-electron ions, multiple vinyl substitution is only weakly stabilizing or destabilizing.
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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 | 0.001 |
| 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) | 0.002 | 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".