Designing Tetraoxa[8]circulenes To Serve as Hosts and Sensors
Bibliographic record
Abstract
In D 4 -symmetric tetraoxa[8]circulenes, alternating fused benzene and furan rings form an octagonal array. These compounds are little known despite their novel properties, which include extended planar π-conjugation and a formally antiaromatic cyclooctatetraene core. Tetraoxa[8]circulenes can be formed by acid-induced cyclocondensations of suitable quinones, but existing methods often give very low yields. In addition, π-stacking of simple tetraoxa[8]circulenes reduces solubility and limits opportunities to form homogeneous mixtures or cocrystals with other compounds. To help make tetraoxa[8]circulenes more useful, we have developed better ways to synthesize them, and we have used these methods to produce awkwardly shaped derivatives with large concave electron-rich aromatic surfaces. These compounds crystallize to form open structures that can accommodate various guests, including C 60 . Analysis of the structures shows that the cyclooctatetraene core of the hosts exhibits surprising variations in C–C bond lengths and conjugation, which appear to be related to the gain or loss of aromaticity. This allows tetraoxa[8]circulenes to serve as sensitive probes of local molecular environment and to be used as sensors of electron-deficient species such as nitroaromatic 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 | 0.000 | 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".