Conformational Solvatomorphism in a [2]Catenane
Bibliographic record
Abstract
The combination of a flexible pyridine-appended ligand (L1) with 4,4′-bipyridine (L2) and cis -protected Pd(II) units, Pd(L′)(NO 3 ) 2, in water yielded a concentration-dependent equilibrium mixture of the corresponding [2]catenanes [Pd 2 (L′) 2 (L1)(L2)] 2 (NO 3 ) 8 and their constituent macrocycles [Pd 2 (L′) 2 (L1)(L2)](NO 3 ) 4 . The cis -protecting units (L′) used were ethylenediamine (en), tetramethylethylenediamine (tmeda), 2,2′-bipyridine (bpy), and 1,10-phenanthroline (phen). Crystallization of the [2]catenanes via slow evaporation of their CH 3 CN/H 2 O (1:1) solutions yielded a single crystalline form in the case of [Pd 2 (2,2′-bpy) 2 (L1)(L2)] 2 (NO 3 ) 8 and two concomitant crystalline forms (solvates) in the case of [Pd 2 (phen) 2 (L1)(L2)] 2 (NO 3 ) 8 . The formation of the [2]catenane is facilitated by noncovalent interactions such as N–H···O, C–H···O, and C–H···π contacts and π···π stacking. The solvates of [Pd 2 (phen) 2 (L1)(L2)] 2 (NO 3 ) 8 revealed differences in the orientation of the amide carbonyl group and conformational differences in the ligands and phen units in the macrocycles and may thus be termed conformational solvatomorphs. The molecular packing in all the structures was found to be driven by intermolecular π···π stacking interactions between the aromatic rings in their cis -protected Pd(II) units. However, because of the awkward shape of the molecules, the closest 2,2′-bpy and phen units in all the structures overlap differently rather than the commonly observed “head-to-tail” or “head-to-head” modes.
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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".