Molecular Tectonics. Use of Br•••aryl Supramolecular Interactions for the construction of Organized Networks from 9,9’-spirobifluorene in the Crystalline State
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Numerous studies, many based on statistical analyses of structural data from the Cambridge Structural Database (CSD, have highlighted the importance of halogenaryl interactions. Although the exact value of the binding energy is still a subject of debate, it is generally agreed that such interactions can play an important role in crystal packing. For example, previous work by Desiraju and collaborators has shown that Braryl interactions generate characteristic supramolecular motifs, which may be useful for designing molecular solids [2]. With this goal in mind, we set out to use 9,9'spirobifluorene (SBF) or tetrabrominated SBF derivatives as tectons [3] and to see if Braryl interactions can be used to build predictable molecular networks. Several features made the SBF core an attractive candidate for this study: 1) SBF has D 2 d symmetry, is rigid and orients its aromatic rings and their substituents in distinct directions of space; 2) the synthesis of SBF derivatives has been described; and 3) derivatives of SBF tend to crystallize readily, frequently as inclusion complexes, which allows the study of interactions between the network and included guests. In the first part of our work, the two different tetrabromo-SBFs (substituted in the meta and para positions, respectively, relative to the spiro center) were synthesized either by a literature procedure or through a new route. Crystals were grown and the structures were solved. Both structures are close packed, and the molecules are linked together by BrAr interactions and also by BrBr contacts. In the second part of our work, we co-crystallized un-substituted SBF with small brominated guests that orient 1, 2, 3 or 4 atoms of bromine in distinct directions. The structures of four co-crystals were solved, and analysis reveals the following points: 1) There are at most only a few direct interactions (CH) between the SBF units themselves; 2) by engaging in Braryl interactions, the brominated guests play a role of connector between SBF units; iii) in this way, Braryl interactions direct the packing of the crystal structures.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.000 | 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) | 0.000 | 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 it