Molecular, Crystal, and Surface Chemistry of the Conformational Polymorphic Forms of <scp>l</scp> -isoleucine
Bibliographic record
Abstract
l -isoleucine exists in two enantiotropically related polymorphs, α and β, which are both zwitterionic in crystalline and solution states. These forms are conformational polymorphs, distinguished by their hydrogen bonding networks, where the α form exhibits a parallel arrangement, while the β form displays nonparallel interactions, reflecting differences between their respective crystal packings. The crystal morphology, molecular conformation and stability, intermolecular (synthonic) interactions, and surface chemistry of both l -isoleucine polymorphs are examined using synthonic and crystallographic modeling. The β form is found to have stronger intermolecular interactions due to its more efficient arrangement of hydrogen bonds, better packing coefficient, and less void space. This is reflected in the lattice energy for the β form, which is about 15% higher than that for the α form, reflecting its shorter and more linear hydrogen bond network. The NH 3 + ···O hydrogen bonding is found to be the strongest bulk (intrinsic) synthon for both forms, reflecting the higher % contribution to their lattice energies. The predicted morphologies for the two forms are found to be almost identical, i.e., displaying a hexagonal cross-section elongated along the b -axis. The anisotropic growth of the morphology reflects the large variation in the attachment energy values for the important morphological facets of both forms. The anisotropic nature of the growth morphology in both forms is further rationalized through examination of the extrinsic (surface-terminated) synthon contributions to the crystal habit surfaces, where the synthons contributing to respective attachment energies are found to be stronger at the capping surfaces than at the more morphologically dominant surfaces.
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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 | 0.000 |
| 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) | 0.000 | 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 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".