Structure–property relationship of donor–acceptor acridones – an optical, electrochemical and computational study
Bibliographic record
Abstract
The synthesis of two neutral acridone derivatives was carried out to design media sensitive chromophores by taking advantage of intramolecular charge transfer (ICT) features. The molecules comprised two different donor-acceptor-donor triads, with absorption maxima at 425 nm and 520 nm, for the ketone and dicyanomethylene derivatives, respectively. The ketone variant exhibited fluorescence at room temperature, whereas the dicyanomethylene derivative was only emissive in frozen hexane. The ketone emission was highly solvatochromic, with Stokes shifts that ranged from 5000 cm(-1) to 10 000 cm(-1). Electrochemically, both compounds displayed similar oxidation potentials at approximately 0.35 V versus ferrocene/ferrocenium, which was anticipated since both systems employ the same ethynylaniline donor portion of the molecule, whereas only the 9-dicyanomethylene derivative showed a reduction peak at -1.5 V vs. Fc/Fc(+). Additional spectroelectro-chemical experiments supported a delocalized cationic charge on the ethynylaniline fragments during oxidation and that during electrochemical reduction the dicyanomethylene moieties show localized anionic charge. All of the experimental observations are finally compared to DFT, TDDFT and NICS(0) computations to gain insight into the transitions involved and deduce the role of the acridone core in stabilizing its oxidized and reduced forms.
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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 | 0.000 |
| 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) | 0.002 | 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".