Exploring the Coordination Chemistry of 3,3′-Di(picolinamoyl)-2,2′-bipyridine: One Ligand, Multiple Nuclearities
Bibliographic record
Abstract
The syntheses, structures, and magnetic properties of three new coordination complexes, tetranuclear [Zn2L(3)(OAc)(OMe)]2·3MeOH·H2O (3), trinuclear [Ni3(L(3))3]·6H2O (4), and a 1-D chain {[Cu2L(3)(OAc)2]2·H2O}n (6), of a polydentate, doubly deprotonated, 3,3'-disubstituted bipyridine ligand [L(3)](2-) are reported. The X-ray crystal structures demonstrate that the ditopic ligand provides a flexible N3 donor set for transition metal ions where each binding pocket shifts from fac to intermediate fac/mer to the mer isomer affording a Ni3 triangle, a Zn4 tetramer, and a 1-D Cu(II) polymer, respectively. This variation in coordination preference is rationalized with the aim of designing future ligands with controlled coordination modes. Magnetic susceptibility studies on 4 reveal it belongs to the rare family of ferromagnetically coupled [Ni3] clusters. In contrast, magnetic studies of the 1-D chain 6 reveal weak antiferromagnetic interactions due to the poor orbital overlap of the singly occupied Cu(II) d(x(2)-y(2)) orbitals with the one-atom bridge that connects them along the Jahn-Teller distortion axis.
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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) | 0.000 | 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 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".