Synthesis and Coordination Chemistry of Hexadentate Picolinic Acid Based Bispidine Ligands
Bibliographic record
Abstract
The synthesis and Cu II, Ni II, Zn II, Co II, and Ga III coordination chemistry of the two isomeric hexadentate N 5 O ligands 6-[[9-hydroxy-1,5-bis(methoxycarbonyl)-7-methyl-6,8-bis(pyridin-2-yl)-3,7-diazabicyclo[3.3.1]nonan-3-yl]methyl]picolinic acid (Hbispa 1a ) and 6-[[9-hydroxy-1,5-bis(methoxycarbonyl)-7-methyl-2,4-bis(pyridin-2-yl)-3,7-diazabicyclo[3.3.1]nonan-3-yl]methyl]picolinic acid (Hbispa 1b ), picolinic acid-appended bispidines, are described. The two ligands are highly preorganized for octahedral coordination geometries and are particularly well suited for tetragonal symmetries, i.e., for Jahn–Teller labile ground states. This is confirmed by all data presented: solid-state structures, solution spectroscopy, electrochemistry, and Cu II complex stabilities. Differences in the preorganization of the two isomers for the Jahn–Teller labile Cu II centers are thoroughly analyzed on the basis of the crystal structures and an angular-overlap-model-based ligand-field analysis.
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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 | 0.001 |
| 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) | 0.002 | 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".