Ring inversion kinetics of p-sulfonatocalix[4]arene and of its Ca(<scp>ii</scp>) and La(<scp>iii</scp>) complexes in water and water-acetone solutions
Bibliographic record
Abstract
The kinetics of the ring inversion of p-sulfonatocalix[4]arene and of its La(III) and Ca(II) 1 ∶ 1 complexes have been studied by 1H NMR in D2O and in a binary mixture 50 ∶ 50% w/w D2O ∶ (CD3)2CO. The exchange between the axial and the equatorial methylene protons was followed. The ring inversion is slowed down in the binary mixture, and in the presence of Ca(II) and La(III) with a larger effect in the latter case. The results of this study are in agreement with a coordination of the sulfonate groups to the second sphere of coordination of the cations. The effect of the solvent and of the cations on the ring inversion rates is purely entropic, with entropies of activation ranging from 2 to 51 J K−1 mol−1, while the enthalpies of activation are constant in the limits of experimental errors, around 60 kJ mol−1. It is proposed that the entropy control of the ring inversion results from the breaking of the structure of the water molecules forming the solvent cage around the calixarene.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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".