Supramolecular Assembly of Bis(benzimidazole)pyridine: An Extended Anisotropic Ligand For Highly Birefringent Materials
Bibliographic record
Abstract
Four new bis(benzimidazole)pyridine (BBP)-containing compounds Zn(BBP)Cl[Au(CN)2], Mn(BBP)[Au(CN)2]2·H2O, Mn(BBP)Br2(MeOH) and Mn(BBP)Cl2(MeOH)·MeOH have been synthesized and structurally characterized and their birefringence values (Δn) determined. The structure of Zn(BBP)Cl[Au(CN)2] contains a hydrogen-bonded dimer of Zn(BBP)Cl[Au(CN)2] units which propagate into a 1D chain through Au-Au interactions, although the crystals are of poor optical quality. The supramolecular structure of Mn(BBP)[Au(CN)2]2·H2 O forms a 1D coordination polymer through chains of Mn(BBP)[Au(CN)2]2 units, each containing one bridging Au(CN)2 and one forming a 2D sheet through Au-Au interactions. The supramolecular structures of Mn(BBP)Br2(MeOH) and Mn(BBP)Cl2(MeOH)·MeOH are very similar, consisting of a complex hydrogen-bonded network between NH imidazole, methanol and halide groups to align BBP building blocks. In the plane of the primary crystal growth direction, the birefringence values of the three Mn-containing materials were Δn=0.08(1), 0.538(3) and 0.69(3), respectively. The latter two birefringence values are larger than in the related 2,2';6'2''-terpyridine systems, placing them among the most birefringent solids reported. These compounds illustrate the utility of extending the π-system of the building block and incorporating hydrogen-bonding sites as design elements for highly birefringent materials and also illustrates the effect on the measurable birefringence of the crystal quality, growth direction and structural alignment of the anisotropic BBP building blocks.
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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) | 0.000 | 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".