Complexation of the caesium cation by the host p-tert-butylcalix[6]arene hexaacetamide
Bibliographic record
Abstract
The complexation of the caesium cation by a p-tert-butylcalix[6]arene hexaacetamide derivative (5,11,17,23,29,35-hexa-tert-butyl-37,38,39,40-hexakis(N,N-diaethylaminocarbonyl)methoxycalix[6]arene) (I) in a binary mixture of deuterated chloroform and acetonitrile was studied by 1H, 133Cs NMR spectroscopy and X-ray crystallography. Different complexes between Cs+ and I with Cs+ ∶ I stoichiometries ranging from 1 to 3 are formed in solution. The 3 ∶ 1 complex is only observed below 250 K, in the presence of excess of Cs+. The structure of the 2 ∶ 1 complex in solution is similar to the distorted partial cone crystal structure in the solid state. The two caesium cations are coordinated to carbonyl and phenolic oxygens, with a short distance of 4.16 Å between them. The dissociation of the 2 ∶ 1 complex follows a dissociative mechanism with ΔH≠ = 58 kJ mol−1 and ΔS≠ = −2 J K−1 mol−1. The activation parameters indicate that the dissociative process is kinetically governed by the successive flipping of two aromatic rings leading to a 1,2,3 alternate conformation of a 1 ∶ 1 complex, similar to the crystal structure of the uncomplexed calix[6]arene hexaacetamide.
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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".