Microwave spectroscopic and computational study of prototypical isocyanates and isothiocyanates
Bibliographic record
Abstract
This thesis outlines the microwave spectroscopic and computational study of prototypical isocyanates (RNCO) and isothiocyanates (RNCS) to better understand how the geometry around nitrogen is influenced by different side chains (R) and terminal chalcogen substitution. Specifically, this thesis describes the comprehensive research done on allyl isothiocyanate (H2C=CHCH2-NCS) (for a comparison with previous results for allyl isocyanate (H2C=CHCH2-NCO)) along with a study of benzyl isocyanate (C6H5CH2-NCO) which was compared to a set of theoretical predictions for benzyl isothiocyanate (C6H5CH2-NCS). Microwave spectroscopy is a useful technique for these investigations as the data collected using the broadband chirped-pulse Fourier transform microwave (cp-FTMW) and the narrowband Balle-Flygare Fourier transform microwave (FTMW) spectrometers are intrinsically sensitive to the underlying molecular geometries of the conformers in each sample. In the allyl-NCS study, microwave transitions were assigned to two conformers including the first report of the lowest energy form and its heavy atom minor isotopologues which enabled a structural derivation. A comparison of the calculated nitrogen hybridization between allyl-NCS and allyl-NCO revealed a change from a ~ sp1.5 environment in allyl-NCO to a ~ sp environment in allyl-NCS which is consistent with the change in the experimentally derived CNC bond angles. For benzyl-NCO, transitions were assigned to the global minimum conformer and its 13C isotopologues. An analysis of the nitrogen hybridization revealed that the benzyl-NCO nitrogen electronic environment is most similar to that of its allyl counterpart and a similar result was confirmed based on the computational predictions for benzyl-NCS when compared with allyl-NCS. A comparison of the results of this thesis with studies of other RNCO and RNCS species in the literature highlights the subtle balance of effects that the R group and terminal chalcogen substitution have on the properties of isocyanates and isothiocyanates.
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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".