Supramolecular structures of three configurational isomers of 1-phenylethanaminium malate(1–)
Bibliographic record
Abstract
In rac-1-phenylethanaminium rac-malate(1−), C8H12N+·C4H5O5−, (I), the anions are linked by two inter-anion O—H⋯O hydrogen bonds into sheets generated by a glide plane and hence containing both enantiomers of the anion. The cations are linked to the anion sheets by three N—H⋯O hydrogen bonds, such that cations of R configuration are bonded to one face of the sheet and cations of S configuration are bonded to the other face. In (R)-1-phenylethanaminium (S)-malate(1−), C8H12N+·C4H5O5−, (III), the anions are again linked by two O—H⋯O hydrogen bonds, in one of which the H atom is disordered over two sites, into sheets very similar to those in (I) but which are generated in (III) by translation and so contain only a single enantiomer. The cations in (III) are linked to the anion sheets by three N—H⋯O hydrogen bonds, but the cations are bonded to only one face of the anion sheet. Co-crystallization of (R)-1-phenylethanamine with rac-malic acid gives the salt (R)-1-phenylethanaminium malate(1−) C8H12N+·C4H5O5−, (II), with a structure very similar to that of (III) but where only ca 75% of the anion sites are occupied by (S)-malate(1−), with the remaining 25% occupied by (R)-malate(1−). The layers in (II) show a significant displacement along the [001] direction compared with those in (III).
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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) | 0.002 | 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".