Inclusion Potential, Polymorphism, and Molecular Isomerism of Metal Dibenzoylmethanates Coordinated with 2-Methylpyridine
Bibliographic record
Abstract
In this study, new complexes of metal(II) (Ni, Zn, Cd) dibenzoylmethanates (DBMs) coordinated with 2-methylpyridine (2-MePy) were prepared and studied for host properties as a function of their structure and molecular isomerism. The novel [Ni(2-MePy) 2 (DBM) 2 ] complex host exists as the trans isomer in five structurally distinct phases comprising two guest-free polymorphs as well as inclusion compounds with benzene, carbon tetrachloride, chlorobenzene, and toluene. All architectures arise from van der Waals packing, the host materials having guest species located in channels or cages. The stability of inclusions correlates with the shape of the cavity space. For zinc dibenzoylmethanate only one 2-MePy unit coordinates to give the [Zn(2-MePy)(DBM) 2 ] complex that does not exhibit inclusion properties. With cadmium dibenzoylmethanate, two polymorphic forms of the composition [Cd(2-MePy) 2 (DBM) 2 ] were isolated. A metastable form contains complex molecules in the trans isomeric state, while a stable form contains cis isomers. As earlier, the ability to form clathrates was attributed only to trans-configured molecules of this type; the presence of a more stable cis form, with a trans-to-cis phase conversion enthalpy gain of as much as 17.2(6) kJ/mol, explains the failure to isolate any inclusion compounds of the Cd complex. The precedent of isolating both cis and trans isomers for the same complex of metal dibenzoylmethanate host is discussed in the context of designing novel materials where the potential for inclusion may be switched through molecular-level control of the isomeric state.
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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".