The neutral complex [Cr<sup>III</sup><sub>4</sub>(μ<sub>3</sub>-O)<sub>2</sub>(μ<sub>2</sub>-CH<sub>3</sub>CO<sub>2</sub>)<sub>7</sub>(<sup>t</sup>bpy<sup>0</sup>)(<sup>t</sup>bpy<sup>•</sup>)]<sup>0</sup> — a tetranuclear Cr(III) species containing a neutral (bpy<sup>0</sup>) and a π-radical anion (bpy<sup>•</sup>)<sup>1–</sup>
Bibliographic record
Abstract
The tetranuclear neutral species [CrIII4(μ3-O)2(μ2-CH3CO2)7(tbpy0)(tbpy•)]0·3THF has been prepared from a mixture of [CrII2(μ2-CH3CO2)4]·2H2O and 4,4′-di-tert-butyl-2,2′-bipyridine (1:2) in tetrahydrofuran (THF) under anaerobic conditions. Black crystals of [CrIII4(μ-O)2(μ-CH3CO2)7(tbpy)2]0 were grown and investigated by X-ray crystallography: a [Cr4O2]8+ butterfly core structure has been identified. In addition, the presence of seven μ2-acetate bridges, a neutral (tbpy0) ligand, and a single π-radical anion (tbpy•)1– have been clearly identified. The magnetic properties have been investigated by solid-state SQUID (superconducting quantum interference device) measurements (2–300 K) and a coupling model is presented. Its X-band electron paramagnetic resonance spectrum has been recorded at 10 and 300 K in toluene solution and successfully simulated. The spin of the (tbpy•)1– radical couples strongly antiferromagnetically to one Cr(III) center (J4 = –129 cm−1). These properties are compared with those reported previously for the monocationic species [CrIII4(μ3-O)2(μ2-CH3CO2)7(bpy0)2](PF6) in Bino et al. (Inorg. Chem. 1991, 30, 856).
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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".