Crystal structure of a tetrakis-substituted pyrazine compound: 2,3,5,6-tetrakis(bromomethyl)pyrazine
Bibliographic record
Abstract
The title compound, C8H8Br4N2, crystallizes in the enanti-omorphic-defining space group P41212 and has a refined Flack x parameter of 0.04 (4). In the asymmetric unit, there are two half-mol-ecules; the whole mol-ecules (A and B) are generated by twofold rotation symmetry. In mol-ecule A, the twofold axis is normal to the pyrazine ring passing through the centre of the ring, while in mol-ecule B, the twofold rotation axis lies in the plane of the pyrazine ring bis-ecting the C-C aromatic bonds. The two mol-ecules are pseudo-mirror images of one another, and the best fit of the two mol-ecules was obtained for inverted mol-ecule B on mol-ecule A, with an r.m.s. deviation of 0.1048 Å and a maximum deviation of any two equivalent atoms of 0.2246 Å. In the crystal, the A mol-ecules are linked by weak C-H⋯Br hydrogen bonds and Br⋯Br inter-actions [3.524 (3) Å], forming a three-dimensional framework. The B mol-ecules are also linked by weak C-H⋯Br hydrogen bonds and Br⋯Br inter-actions [3.548 (3) Å], forming a three-dimensional network that inter-penetrates the network of A mol-ecules.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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 teacher head, 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".