Ditopic receptors of hexaamide derivatives derived from hexahomotrioxacalix[3]arene triacetic acid
Bibliographic record
Abstract
The lower rim functionalized hexahomotrioxacalix[3]arene hexaamide 7 having an amino acid moiety with cone conformation was synthesized from triol 1 by a stepwise reaction. The different extractability for alkali metal ions, transition metal ions, and alkylammonium ions from water into dichloromethane was discussed. Owing to the strong intramolecular hydrogen bond between the neighboring NH and CO groups in hexaamide 7, its affinity to metal cations was weakened. Hexaamide 7 shows a single selectivity to n-BuNH3+. The anion complexation of hexaamide 7 was also studied by 1H NMR titration experiments. Hexaamide 7 binds halides through the intermolecular hydrogen bond among the NH hydrogens of the amide in a 1:1 fashion in CDCl3. Thus, hexaamide 7 serves as a heteroditopic receptor that can complex with halides (Cl, Br) and n-BuNH3+ at the same time. The association constants calculated from the chemical shift changes of the amide protons are Ka = 536 ± 32 (mol/L)1 for Cl and Ka = 230 ± 17 (mol/L)1 for Br.Key words: hexahomotrioxacalix[3]arenes, ionophores, molecular recognition, ammonium ion, ditopic receptor.
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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".