Structure and Segmental Motions in Symmetrically Substituted Poly(ferrocenylsilanes): A Carbon-13 CPMAS NMR Contact Time Study
Bibliographic record
Abstract
The structure and thermal behavior of two organometallic polymers, poly(ferrocenyl dimethylsilane) ( I ) and poly(ferrocenyl di- n -butylsilane) ( II ), have been examined using a variety of physical characterization methods which reveal differences in their crystalline structures and associated segmental librations. In addition to examination with differential scanning calorimetry and wide-angle X-ray scattering, solid-state 13 C NMR spectra were acquired for a wide range of 1 H− 13 C contact times. The spectra of I at room temperature exhibit two isotropic chemical shifts for the methyl groups, indicating the presence of different environments. The initial cross-polarization (CP) times of crystalline, protonated carbons are interpreted with reference to values found in the literature. The main chains of both polymers were found to be fairly rigid on the time scale of T CH, but the side chains of II are very disordered. The relevance of the 13 C measurements at room temperature is discussed with regard to a higher temperature transition indicated in the DSC trace of II .
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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) | 0.001 | 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".