Synthesis of a quinoxaline dimer and trimer via Yamamoto coupling
Bibliographic record
Abstract
Quinoxalines are an important class of compounds that can exhibit properties such as luminescence and liquid crystal phases. The corresponding quinoxaline dimers and their cyclotrimers, in contrast, have received little attention. We report the synthesis and characterization of a novel tetrakis(dialkoxyphenyl)biquinoxaline derivative (1) and the corresponding novel hexakis(dialkoxyphenyl)-1,4,7,10,13,16-hexaazatrinaphthylene (2) using the nickel-mediated Yamamoto coupling as a key step. The resulting compounds show solvent-dependent emission spectra in solution, suggesting a donor–acceptor architecture with charge separation in the excited state. Preliminary mesophase characterization reveals that both compounds also exhibit columnar mesophases, as shown by polarized optical microscopy and differential scanning calorimetry, and form glasses upon cooling to room temperature.
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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) | 0.003 | 0.002 |
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".