A Triple‐Decker Heptadecanuclear (Cu<sup>II</sup>)<sub>15</sub>(Cr<sup>III</sup>)<sub>2</sub> Complex Assembled from Pentanuclear Metallacrowns
Bibliographic record
Abstract
Abstract Reaction of the pentanuclear CuII metallacrown [Cu5(ahpha)4](ClO4)·4H2O (ahpha2– is the dianion of 3‐amino‐3‐(hydroximino)propanehydroxamic acid), with Cr(C2O4)33– led to the formation of a heptadecanuclear complex {[Cu5(ahpha)4]3[Cr(C2O4)3]2·4H2O}·8H2O·1/3(DMF) (1·8H2O·1/3(DMF)). This compound contains three stacked Cu5(ahpha)42+ building blocks, linked by axial bonds between Cu2+ ions of one Cu5 metallacrown and hydroxamate oxygen atoms of the neighboring Cu5 unit. Two Cr(C2O4)33– anions are bonded to the two lateral Cu5(ahpha)42+ cations through axial Cu–O(oxalate) bonds. The formation of 1 may be considered the first example of metallacrown trimerization caused by anion metathesis. The compound contains 10 × 13 Å voids (about 25 % of crystal volume), filled with solvate water molecules. The magnetic properties (χMT vs. T) could be fitted as the superposition of the magnetism of 3χMT(CuII5) and 2χMT(CrIII). Exchange interactions within the CuII5 units were fit in the framework of a model based on the Hamiltonian H(CuII5) = –2J1(S1.S5 + S2.S5 + S3.S5 + S4.S5) –2J2(S1.S2 + S2.S3 + S3.S4 + S4.S1), where S5 represents the central Cu2+ ions' spins and the other spin operators correspond to the peripheral Cu2+ ions. With other possible interactions taken into account using a molecular field approach, the best fit correspondedto J1 = –153(5) cm–1, J2 = –71(2) cm–1 and zJ′ = –0.058(4) cm–1.
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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".