Formation of Host-Guest Complexes of β-Cyclodextrin and Perfluorooctanoic Acid
Bibliographic record
Abstract
Structural characterization and dynamic properties of solid-state inclusion complexes of β-cyclodextrin (β-CD) with perfluorooctanoic acid (PFOA) were investigated by (19)F/(13)C solid-state and (19)F/(1)H solution NMR spectroscopy. The complexes in the solid state were prepared using dissolution and slow cool methods, where thermal analyses (DSC and TGA), PXRD, and FT-IR results provided complementary support that inclusion complexes were formed between β-CD and PFOA with variable stoichiometry and inclusion geometry. (19)F DP (direct polarization) and (13)C CP (cross-polarization) with magic-angle spinning (MAS) solids NMR, along with (19)F/(1)H solution NMR were used to characterize the complexes in the solid and solution phases, respectively. The dynamics of the guest molecules in the inclusion complexes (ICs) were studied using variable temperature (VT) (19)F DP/MAS NMR experiments in the solid state. The guest molecules were observed to be in several different molecular environments, providing strong evidence of variable host-guest stoichiometry and inclusion geometry, in accordance with the preparation method of the complex and the conformational preference of PFOA. It was concluded from PXRD that β-CD and PFOA form inclusion complexes with "channel-type" structures. Variable spin rate (VSR) (19)F DP/MAS NMR was used to assess the phase purity of the complexes, and it was revealed that slow cooling resulted in relatively pure phases. In the solution state, (1)H and (19)F NMR complexation-induced chemical shifts (CISs) of β-CD and PFOA, respectively, provided strong support for the formation of 1:1 and 2:1 β-CD/PFOA inclusion complexes. The dynamics of the guest molecule in the β-CD/PFOA complexes in D(2)O solutions were probed using VT (19)F NMR and revealed some guest conformational and exchange dynamics as a function of temperature and the relative concentrations of the host and guest.
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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".