Host–guest complexes of conformationally flexible<i>C</i>-hexyl-2-bromoresorcinarene and aromatic<i>N</i>-oxides: solid-state, solution and computational studies
Bibliographic record
Abstract
Host–guest complexes of C -hexyl-2-bromoresorcinarene (BrC6) with twelve potential aromatic N -oxide guests were studied using single crystal X-ray diffraction analysis and 1 H NMR spectroscopy. In the solid state, of the nine obtained X-ray crystal structures, eight were consistent with the formation of BrC6- N -oxide endo complexes. The lone exception was from the association between 4-phenylpyridine N- oxide and BrC6, in that case the host forms a self-inclusion complex. BrC6, as opposed to more rigid previously studied C -ethyl-2-bromoresorcinarene and C -propyl-2-bromoresorcinarene, undergoes remarkable cavity conformational changes to host different N -oxide guests through C–H···π (host) interactions. In solution phase CD 3 OD/CDCl 3 (1:1 v/v), all twelve N -oxide guests form endo complexes according to 1 H NMR; however, in more polar CD 3 OD/DMSO- d 6 (9:1 v/v), only three N -oxides with electron-donating groups form solution-phase endo complexes with BrC6. In solid-state studies, 3-methylpyridine N -oxide+BrC6 crystallises with both the upper- and lower-rim BrC6 cavities occupied by N -oxide guests. Computational DFT-based studies support that lower-rim long hexyl chains provide the additional stability required for this ditopic behaviour. The lower-rim cavity, far from being a neutral hydrophobic environment, is a highly polarizable electrostatically positive surface, aiding in the binding of polar guests such as N -oxides.
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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) | 0.001 | 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 | 0.000 |
| 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".