Role of Coordinated Water and Hydrogen‐Bonding Interactions in Stabilizing Monophenoxido‐Bridged Triangular Cu<sup>II</sup>M<sup>II</sup>Cu<sup>II</sup> Compounds (M = Cu, Co, Ni, or Fe) Derived from <i>N</i>,<i>N′</i>‐Ethylenebis(3‐methoxysalicylaldimine): Syntheses, Structures, and Magnetic Properties
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Bibliographic record
Abstract
Abstract The syntheses, structures, and magnetic properties of the trinuclear triangular compounds [{Cu II L 1 } 2 Cu II (H 2 O) 2 ](ClO 4 ) 2 · H 2 O ( 1 ) and [{Cu II L 1 } 2 M II (H 2 O) 2 ](ClO 4 ) 2 {M = Ni ( 2 ), Co ( 3 ), Fe ( 4 )} derived from N , N ′‐ethylenebis(3‐methoxysalicylaldimine) (H 2 L 1 ) are described. Compound 1 crystallizes in the monoclinic P 2 1 / n space group, while the crystal system for the isomorphous compounds 2 – 4 is monoclinic P 2 1 / c . In the cations of these compounds, two copper(II) ions occupy the salen type N 2 O 2 cavity of two [L 1 ] 2– ligands, while one phenoxido and one methoxy oxygen atom of each of these two [Cu II L 1 ] moieties coordinate to a central metal ion, which results in the formation of the trinuclear Cu II 2 M II systems in which the two pairs of central ··· terminal metal ions are monophenoxido‐bridged. In addition, to the two phenoxido bridges, the central metal ion is coordinated to two methoxy and two water oxygen atoms. The coordinated water molecules are strongly hydrogen bonded to the phenoxido and methoxy oxygen atoms. The presence of the coordinated water molecules and the interaction of these water molecules with the phenoxido and methoxy oxygen atoms are proposed to be the governing factors for the stabilization of the rare example of the monophenoxido‐bridged Cu II 3 compound 1 and of the first examples of the monophenoxido‐bridged Cu II 2 M II compounds 2 – 4 . The three metal ions define an isosceles triangle. The phenoxido bridge angles in these compounds are significantly obtuse and vary between 121.10(12)° and 129.84(13)°. On the other hand, the trinuclear cores are highly twisted as evidenced from the range of the dihedral angles (58.5–143.7°) between the basal planes of the terminal and the central metal ions. The variable‐temperature (2–300 K) magnetic susceptibilities of compounds 1 – 4 have been measured. The magnetic data for 1 have been analyzed by using a model of two exchange integrals for the two pairs of adjacent metal ions, while one J value is considered for the other three complexes. The exchange integrals obtained are: Cu II 3 compound 1 : J 1 = –97.6 cm –1 , J 2 = –89.5 cm –1 ; Cu II 2 Ni II compound 2 : J = –25.4 cm –1 ; Cu II 2 Co II compound 3 : J = –9.0 cm –1 ; Cu II 2 Fe II compound 4 : J = –6.5 cm –1 . These moderate to weak antiferromagnetic interactions in 1 – 4 are related to the twisting of the trinuclear cores. The relative order of the exchange integrals can been understood from the nature of the magnetic orbitals. The structural and magnetic results have been compared with previously reported related compounds.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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 it