Role of hydrogen in ground and excited state studies of 2-aryl-3-hydroxychromenones in different solvents
Bibliographic record
Abstract
Radical scavenging activity (%SC) of three 2-heteroaryl 3-hydroxy chromenones (3-HCs) relative to 3-hydroxy flavones (3-HF) has been determined, using 2,2-diphenyl-1-picrylhydrazyl (DPPH) as a radical scavenger both in methanol (MeOH) and acetonitrile (ACN) as solvents. Among the three 3-HCs, 2-(furan-2-yl)-3-hydroxy-4 H-chromen-4-one (FHC), 3-hydroxy-2-(thiophene-2-yl)-4H-chromen-4-one (THC), and 3-hydroxy-2-(pyrrol-2-yl)-4H-chromen-4-one (PHC), the last 3-HC was included in our earlier reported studies on absorption, emission, and excitation spectra. Detailed studies on the excited state intramolecular proton transfer (ESIPT) on PHC relative to other three 3-HCs have been given. Order of %SCs is PHC > FHC > THC > 3-HF in MeOH and PHC > FHC ≈ THC > 3-HF in ACN, which are similar to that of intensity ratio of normal and tautomeric forms (I N* /I T* ). Both %SC and I N* /I T* depend upon the potential of hydrogen of 3-hydroxy in 3-HCs in their ground and excited states, respectively. It has been found that for PHC, I N* /I T* and %SC are distinctly high compared with other chromenones. It is concluded that the determination of %SC can be as important as I N* /I T* for these.
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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 | 0.000 |
| 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".