Syntheses and Structures of Isomeric Diaminotriazinyl-Substituted 2,2′-Bipyridines and 1,10-Phenanthrolines
Bibliographic record
Abstract
Isomeric 2,2'-bipyridines 4a-6a and 1,10-phenanthrolines 7a-9a with two diaminotriazinyl (DAT) substituents were synthesized to explore their dual ability to direct association by the chelation of metals and the characteristic hydrogen bonding of DAT groups. Crystals of compounds 4a-6a and 7a-9a were grown under diverse conditions, and their structures were solved by X-ray crystallography. Analysis revealed multiple shared features analogous to those observed in the structures of simpler DAT-substituted pyridines 1-3. For example, the bipyridines and phenanthrolines favor flattened conformations except in the cases of compounds 8a and 9a, where the patterns of substitution prevent the DAT groups from lying in the plane of the phenanthroline core. As expected, the DAT groups form approximately coplanar hydrogen bonds according to standard motifs I-III, which play a key role in directing molecular organization. However, the structures of simple pyridines 1-3, which favor efficiently packed chains and sheets, differ predictably from those of bipyridines 4a-6a and phenanthrolines 7a-9a in two ways: (1) The larger number of DAT groups in compounds 4a-9a typically leads to complex three-dimensional networks held together by a larger number of hydrogen bonds per molecule, and (2) the need to respect multiple directional interactions prevents compounds 4a-9a from forming closely packed structures, and significant quantities of guests are included. Together, these observations confirm the effectiveness of incorporating special groups such as DAT within more complex molecular structures to control association according to reliable patterns. Bipyridines 4a-6a and phenanthrolines 7a-9a promise to be particularly rich sources of new supramolecular chemistry because they have well-defined molecular topologies and a dual ability to direct association by chelating metals and by engaging in multiple hydrogen bonds according to reliable patterns.
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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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".