A BROADBAND ROTATIONAL SPECTROSCOPIC AND THEORETICAL STUDY OF CIS AND TRANS (-)-CARVEOL
Bibliographic record
Abstract
Carveol, a primary constituent in spearmint and peppermint oil, is a monocyclic monoterpenoid alcohol that is produced in nature by the photooxidation of limonene.$^{1}$ Structurally, carveol contains two chiral centers with three substituents (methyl group, hydroxyl group, and propylene group) attached to it’s cyclohexane ring. The combination of the three flexible substituents, ring puckering, and two chiral centers introduce a complex conformational topography that is non-trivial to elucidate. However, a thorough study of the topology of chiral carveol may provide valuable insights into complex conformational dynamics, as well as chirality recognitions studies. We believe chirped-pulse Fourier transform microwave spectroscopy (CP-FTMW) is an excellent tool for this investigation as it is able to unambiguously distinguish structural conformers within a complex mixture.$^{2}$ The broadband rotational spectrum of cis and trans (-)-carveol was recorded using a chirped pulse Fourier Transform microwave spectrometer in the 2-6 GHz region.$^{3}$ To aid in experimental assignment, a theoretical conformational search was carried out using a combination of a two dimensional potential energy scan, which scans over the propylene group and hydroxyl group, and the Conformer–Rotamer Ensemble Sampling Tool (CREST).$^{4}$ The theoretical results yielded a total of 23 conformers for the trans and 19 for the cis. Utilizing these results, a total of five experimental conformers were then assigned: two for the trans conformer and three for the cis conformer. For trans, it was determined both experimental conformers occupy the equatorial position. For the cis conformer, two equatorial and one axial conformer was experimentally assigned. The conformational cooling pathways and intermolecular interactions within each conformer were also analyzed to further understand the conformational landscape of cis and trans (-)-carveol.\n\n1. J. Laothawornkitkul, J. E. Taylor, N. D. Paul and C. N. Hewitt, New Phytol., 2009, 183, 27–51.; 2. G. Barratt Park, and Robert W. Field, J. Chem. Phys., 2016, 144, 20090.; 3. N. A. Seifert, J. Thomas, W. Jäger and Y. Xu, Phys. Chem. Chem. Phys., 2018, 20, 27630–27637.; 4. P. Pracht, F. Bohle, S. Grimme, Phys. Chem. Chem. Phys. 2020., 22(14), 7169-7192
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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".