Effect of the position of the substituent in the electrochemical reduction of nitro-substituted benzenesulfonyl chlorides
Bibliographic record
Abstract
The electrochemical reduction of a series of nitro-substituted benzenesulfonyl chlorides is investigated. The results of the electrochemical study are analysed with the assistance of theoretical calculations. The study shows that the electron transfer mechanism depends on the position of the nitro substituent on the phenyl ring. The 3-nitrobenzenesulfonyl chloride follows a stepwise mechanism where the reduction leads to an intermediate radical anion. For the 4-nitrobenzenesulfonyl chloride, 2-nitrobenzenesulfonyl chloride, and 2,4-nitrobenzenesulfonyl chloride, the reduction follows a “sticky” dissociative mechanism, where the electron transfer and S–Cl bond cleavage are concerted. The dissociation products (arylsulfinyl radical and chloride anion) show strong interactions. The difference in behaviour is associated with the overlap of the π* orbital and the S–Cl σ* orbital for the latter three compounds. The through resonance stability of the arylsulfinyl radicals for the para and ortho nitro-substituted compounds facilitates the dissociation of the reduced structures. Upon reduction, the 3-nitrobenzenesulfonyl chloride and 4-nitrobenzenesulfonyl chloride, also produce the corresponding diaryl disulfones, which are easier to reduce that the parent molecules and hence induce an interesting autocatalytic mechanism. Such a mechanism, which depends on the concentration and the scan rate, does not take place with the 2-nitrobenzenesulfonyl chloride and 2,4-dinitrobenzenesulfonyl chloride due to the sterical hindrance of the nitro substituent at the ortho position, as it prevents the formation of the disulfones.
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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) | 0.000 | 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".