An Ytterbium-Pyrazine Square [(C <sub>5</sub> H <sub>4</sub> Me) <sub>2</sub> Yb <sup>III</sup> (pyz <sup>•–</sup> )] <sub>4</sub> Formed by Reversible Electron Transfer and Concomitant Self-Assembly
Bibliographic record
Abstract
Pyrazine (pyz) has been used extensively in coordination chemistry to manifest electron delocalization in mixed-valent compounds and strongly coupled materials. In the current work, using a Yb II precursor, [(C 5 H 4 Me) 2 Yb II (THF) 2 ] ( 1 ), a molecular square [(C 5 H 4 Me) 2 Yb III (pyz •– )] 4 · 1 / 2 (C 7 H 5 F 3 ) ( 2 ) was synthesized by metal-ligand redox cooperativity. Complex 2 shows evidence of charge transfer from Yb II to pyrazine in a range of studies including structural analysis, magnetometry, vibrational spectroscopy, X-ray absorption near-edge structure spectroscopy, and electronic structure calculations. DFT calculations support the assignment of low-energy bands in the UV–vis spectrum as pyrazine-SOMO-to-metal-4f charge transfer. Magnetic studies reveal a Yb-pyz •– exchange coupling of −3.6 cm –1 and pyz •– -pyz •– coupling of −18.6 cm –1 for the radical bridged Yb-square complex.
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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) | 0.002 | 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 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".