Isomorphous crystal structures of chlorodiacetylene and iododiacetylene derivatives: simultaneous hydrogen and halogen bonds on carbonyl
Bibliographic record
Abstract
The crystal structures of tert-butyl (5-chloropenta-2,4-diyn-1-yl)carbamate, C10H12ClNO2 (II), and tert-butyl (5-iodopenta-2,4-diyn-1-yl)carbamate, C10H12INO2 (IV), are isomorphous to previously reported structures and accordingly their molecular and supramolecular structures are similar. In the crystals of (II) and (IV), molecules are linked into very similar two-dimensional wall organizations with antiparallel carbamate groups involved in a combination of hydrogen and halogen bonds (bifurcated N—H...O=C and C[triple-bond]C—X...O=C interactions on the same carbonyl group). There is no long-range parallel stacking of diynes, so the topochemical polymerization of diacetylene is prevented. A Cambridge Structural Database search revealed that C[triple-bond]C—X...O=C contacts shorter than the sum of the van der Waals radii are scarce (only one structure for the C[triple-bond]C—Cl...O=C interaction and 13 structures for the similar C[triple-bond]C—I...O=C interaction).
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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 | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".