Polynuclear lanthanide (Ln) complexes of a tri-functional hydrazone ligand – mononuclear (Dy), dinuclear (Yb, Tm), tetranuclear (Gd), and hexanuclear (Gd, Dy, Tb) examples
Bibliographic record
Abstract
The lanthanide coordination chemistry of a tri-functional vanillin-hydrazone-oxime ligand reveals a variety of different products, depending on reaction conditions, with mono-nuclear (Dy), dinuclear (Yb, Tm), tetranuclear (Gd) and hexanuclear (Gd, Tb, Dy) examples. The Ln6 (Ln = Gd, Dy, Tb) complexes form in the presence of both triethylamine and acetic acid, and have unique, flat hexanuclear structures built on a μ3-O bridged triangular core, with the six lanthanide ions bridged further through μ-acetate and μ-Ohydrazone connections in an expanded fused triangular array. Similar reaction conditions with Yb(III) and Tm(III) lead preferentially to dinuclear systems, while in the presence of a competitive benzoate ligand a rectangular Gd4 complex results. Variable temperature DC magnetic data for the Gd(III) complexes reveal weak antiferromagnetic exchange. AC magnetic data on the other polynuclear complexes down to 2 K, both in the absence and presence of external bias fields, revealed no significant out of phase signals normally indicative of SMM behavior. However, the mononuclear Dy(III) complex shows frequency dependent AC signals and maxima in the temperature range 2-20 K in the presence of an external bias field, indicative of SMM behaviour, with Ueff = 36(1) K, and τ0 = 4.4(2) × 10(-6) s.
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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".