Hydrogen-bonding behaviour of benzene-1,2,4,5-tetracarboxylic acid: supramolecular structures of different dimensionality in the 2:1 adducts formed with 4,4′-bipyridyl and hexamethylenetetramine
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Bibliographic record
Abstract
Co-crystallization of benzene-1,2,4,5-tetracarboxylic acid, C10H6O8, with 4,4'-bipyridyl, C10H8N2, or with hexamethylenetetramine, C6H12N4, from methanol solutions yields in each case a 2:1 salt, [(C10H9N2)+]2.[(C10H4O8)2-] (1) and [(C6H13N4)+]2.[(C10H4O8)2-] (2). In (1) the carboxylate anions lie across centres of inversion, but they contain no intramolecular O-H...O hydrogen bonds: the cations and anions are linked by strong O-H...N and N-H...O hydrogen bonds into a chain-of-rings, and these chains are further linked into a three-dimensional framework structure by means of C-H...O hydrogen bonds and aromatic pi...pi stacking interactions. Compound (2) contains two independent three-molecule aggregates, comprising a central anion and two cations, linked to the anion by means of short N-H...O hydrogen bonds. One of these aggregates is centrosymmetric, but the other is not, and the two types of anion both form two intramolecular O-H...O hydrogen bonds. The two types of three-molecule aggregate, in which all the anions are virtually parallel, are linked by short C-H...O hydrogen bonds into a molecular staircase.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 it