Quantitative Scale for the Extent of Conjugation of Carbonyl Groups: “Carbonylicity” Percentage as a Chemical Driving Force
Bibliographic record
Abstract
Despite the carbonyl group being one of the most pervasive chemical building blocks in natural, synthetic, and industrial processes, its exact description in terms of precise quantification of the degree of carbonyl conjugation has yet to be determined. The present work suggests a novel yet simple method for quantifying the conjugation in general carbonyl groups (such as ketones, aldehydes, carboxylic acids and their respective halogenides, amides, etc.) on a linear scale, defined as the "carbonylicity scale". This was achieved by use of the computed enthalpy of hydrogenation (DeltaH(H2)) of the > C=O group in the compounds examined. In the present conceptual work, the DeltaH(H2) value for formate ion is used to define complete conjugated character (carbonylicity = +100%), while formaldehyde represents complete absence of conjugation (carbonylicity = 0%). The component DeltaH(H2) values were computed at differing levels of theory, providing a nearly "method-independent" measure of carbonylicity computationally. A total of 49 common carbonyl compounds were used as accuracy scoring criteria of the methodology. For the compounds examined, correlations have been made between the computed carbonylicity percentage and the > C=O proton affinities, IR frequencies, and their reactivity values in a nucleophilic addition reaction. Selected chemical reactions were also studied to illustrate the utility of carbonylicity scale. Examples herein include demonstrating that change in the carbonylicity value represents a thermodynamic driving force in acylation reactions. The definition was extended to substituted thiocarbonyl and imino compounds.
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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 | 0.003 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".