Solid State NMR Spectroscopic Investigations of Model Compounds for Imidazole-Based Proton Conductors
Bibliographic record
Abstract
The temperature dependence and the exact geometry of slow molecular reorientations in imidazolium methyl sulfonate are investigated using modern one-dimensional MAS exchange spectroscopy. Earlier high-temperature studies have evidenced a fast 180° flip motion of the imidazole ring, which is shown here to slow on cooling and is believed to be a prototypical molecular process involved in Grotthus-type proton transport in imidazole-based proton conductors intended for fuel cell applications. It is further shown that valuable information on the relative orientations of CH and NH dipolar coupling tensors with respect to the chemical shift anisotropy tensors of the respective heteronuclei can be obtained from the MAS exchange data as well as from static 13 C and 15 N line shapes, without the necessity of performing more involved single-crystal NMR experiments. The principal axes of the CSA tensors are found to not coincide with the CH or NH bond axes, in contrast to earlier assumptions involving similar compounds. Imidazole itself is shown to be more complex than might be expected, based on its simple structure. Implications on earlier studies of pure imidazole, where ring flips were claimed to be absent, are discussed.
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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".