Antiferromagnetically Coupled Dimeric Dodecacopper Supramolecular Architectures of Macrocyclic Ligands with a Symmetrical μ<sub>6</sub>-BO<sub>3</sub><sup>3–</sup> Central Moiety
Bibliographic record
Abstract
Reactions between 2,6-diformyl-4-alkyl(R)-phenol (R = CH3 or C(CH3)3) and 1,3-diamino-2-hydroxypropane (1,3-DAP) in the presence of copper(II) salts (Cu(BF4)2·6H2O, Cu(ClO4)2·6H2O/H3BO3/Ar) and triethylamine (TEA) in a single pot result in self-assembly of dimeric dodecacopper supramolecular architectures of 30-membered hexatopic macrocyclic ligands (H6L4 and H6L5) with unique and fascinating structures having the BO3(3-) anion as the central species bonded to all six copper centers in a symmetrical fashion (μ6-BO3(3-)). A number of closely related macrocyclic hexacopper complexes are reported: {[Cu6(L4)(μ6-BO3)(μ-H2O)(C3H7NO)2(BF4)][BF4]2·3C3H7NO}2 (1) (DMF = C3H7NO), {[Cu6(L4)(μ6-BO3)(μ-C3H7NO)3][ClO4]3·3C3H7NO}2 (2), {[Cu6(L5)(μ6-BO3)(μ-OH)(H2O)3(C3H7NO)][BF4]2·6C3H7NO·4C2H5OH·2H2O}2 (3), {[Cu6(L5)(μ6-BO3)(μ-CH3OH)(CH3OH)2][ClO4]3·10H2O}2 (4), and {[Cu6(L5)(μ6-BO3)(μ-CH3CO2)(μ-CH3O)(CH3OH)][BF4]·13CH3OH·8H2O}2 (5). A polymeric side product {[Cu2(H2L2)(CH3OH)(BF4)][BF4]}n (6), involving a 2 + 2 macrocyclic ligand, was also isolated and structurally characterized. Complex 6 involves dinuclear copper(II) units linked through BF4(-) anions to form a novel 1D single-chain polymeric coordination compound. This appears to be the first report in which a central BO3(3-) species is linked to six copper(II) ions held together by a single macrocyclic ligand through three μ1,1-O(BO3(3-)) and three μ1,3-O(BO3(3-)) bridges. In complexes 1-5 the BO3(3-) is present in the center of the macrocyclic cavity and is bonded to all six metal centers arranged in a benzene-like hexagonal array. In the hexagonal array there are alternate double (μ-alkoxide and μ1,3-O(BO3(3-))) and (μ-phenoxide and μ1,1-O(BO3(3-))) bridges between the Cu(II) centers. The symmetrical hexa-bridging nature of μ6-BO3(3-) is unprecedented in transition metal complex chemistry, and along with alkoxide and phenoxide bridges in the equatorial plane provides effective pathways for an overall antiferromagnetic exchange interaction between six copper(II) centers. In 1, 3, and 5 the BO3(3-) moiety is produced in one step (synthetic) by an unusual copper(II)-macrocycle complex catalyzed hydrolysis of BF4(-) ion in methanol. In 2 and 4 the central species (BO3(3-)) comes from boric acid (H3BO3) which is added to reaction mixture of Cu(ClO4)2/H6L4/H6L5 under inert conditions to confirm the identity of the central species.
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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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".