Synthesis, characterization of phenyl (2,4-dinitro-1-naphthyl) thioethers, kinetic and mechanistic study of their hydrazinolysis in methanol
Bibliographic record
Abstract
The rate of reactions of aryl-2,4-dinitro-1-naphthyl sulfides with hydrazine in large excess in methanol were followed spectrophotometrically at λ max = 515 nm corresponding to the formation of 1-hydrazino-2,4-dinitronaphthalene anion. The rate of reaction is measured at different temperatures under pseudo first-order condition. The reaction rate is not subject to catalysis by the hydrazine. The second-order rate constant (k N ) at 25 °C depended marginally on the nature of the 4′-substituent. Low enthalpy and negative entropy of activation values suggested a second-order nucleophilic substitution mechanism for the reaction, further supported by a linear plot ( r = 0.927) with the isokinetic temperature of the reaction “β” predicted to be 1382 K. The isokinetic temperature significantly exceeds the experimental range (298–318 K), indicating enthalpy-controlled reaction kinetics. The correlations of σ-Hammett constants with k N values gave good correlation coefficients ( r = 0.9939–0.9571) with ρ values ranged between 0.35 and 0.25 depending on temperatures. The plot of the logarithmic of the rate and the p K a of the nucleophile gave value of β LG value (−0.14, r = 0.97) suggested that the transition state involving in the fast step is consistent with substrates having good leaving groups.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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) | 0.000 | 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".