Polymorphism in a π-Stacked 1,3,2-Dithiazolyl Radical: Pyridyl-1,3,2-Dithiazolyl
Bibliographic record
Abstract
Pyridyl-1,3,2-dithiazolyl PyDTA ( 1 ) has been synthesized and its electronic structure has been probed by cyclic voltammetry, electron paramagnetic resonance spectroscopy, and density functional theory calculations. The results demonstrate that the spin distribution and redox properties of the radical are intermediate between those observed for the isoelectronic benzo- and pyrazino-1,3,2-dithiazolyl radicals. Crystals of 1 can be grown by vacuum sublimation as two polymorphs. The kinetically favored form 1α grows as purple/black blocks or rods and crystallizes in the noncentric space group P 2 1, while the thermodynamically favored 1β phase forms green/black shards and crystallizes in the centric space group P 2 1 /n . The structures of both 1α and 1β comprise layers of head-to-head π*−π* dimers in the ab plane. The two structures differ in the orientation of the π-dimers along the stacks. In 1α dimers are aligned head-to-head, while in 1β the orientation of the dimers alternates in a head-over-tail fashion, so as to produce an approximate doubling of the crystallographic c -axis in relation to 1α . Variable temperature magnetic susceptibility measurements reveal that both phases are essentially diamagnetic at low temperatures. Above 180 K (for 1β ) and above 250 K (for 1α ) the free Curie spin count for both polymorphs begins to rise, indicating a weakening of the π*−π* dimers in the solid state.
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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) | 0.001 | 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".