Computational Determination of Aqueous p<i>K</i><sub>a</sub> Values of Protonated Benzimidazoles (Part 1)
Why this work is in the frame
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Bibliographic record
Abstract
Benzimidazoles are the organic compounds investigated in this work. The experimental determination of the pKa values of protonated benzimidazoles in water is a challenge because of their low solubility. In addition, some derivatives are involved in tautomeric equilibria which increase the complexity of the theoretical pKa determinations. In the present study, different approaches are considered to develop a methodology for the accurate prediction of aqueous pKa values of protonated benzimidazoles at 298.15 K. We have considered different reaction schemes for approximating the acid dissociation equilibrium; two distinct equations are used for the calculation of pKa values, and a number of levels of theory and empirical corrections are applied in the process of working toward this aim. The best correlations between the experimental and calculated data are obtained at the B3LYP/6-31+G(d,p)-PCM(opt) level of theory. The predictive capabilities of the methodologies attempted are tested with two compounds that were not included in the set of benzimidazoles initially investigated. The direct calculations differ significantly from the expected values, but the pKa values calculated using the correlation equations are very similar and in reasonable agreement with the expected pKa values.
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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 | 0.000 |
| 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) | 0.000 | 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 it