Bis(μ-2-{bis[(2-oxidobenzylidene)amino]methyl}phenolato)bis[(tetrahydrofuran)samarium(III)] tetrahydrofuran disolvate

Li, Li; Zhou, Yuan; Yuan, Fang

doi:10.1107/s1600536812015759

Cited by 2 publications

(1 citation statement)

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“…With the exception of H 3 salmp, for which quite a few complexes have been synthesized and structurally characterized up to date [ 10 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ], less is known about the other two classes of shortened Schiff base derivatives [ 7 , 11 , 19 , 20 , 31 ]. Nevertheless, it is undeniable the usefulness of all these ligands for the synthesis of efficient catalysts [ 15 , 16 , 17 ], their use for metal sequestration in solution [ 32 ], synthesis of biomimetic systems [ 24 ] and the fascinating magnetic properties of the corresponding oligonuclear clusters [ 19 , 20 , 23 , 24 , 26 , 27 , 28 , 31 , 33 ].…”

Section: Introductionmentioning

confidence: 99%

Selective Formation, Reactivity, Redox and Magnetic Properties of MnIII and FeIII Dinuclear Complexes with Shortened Salen-Type Schiff Base Ligands

Rigamonti

Zardi

Carlino

et al. 2020

IJMS

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The reactivity of the shortened salen-type ligands H3salmp, H2salmen and H2sal(p-X)ben with variable para-substituent on the central aromatic ring (X = tBu, Me, H, F, Cl, CF3, NO2) towards the trivalent metal ions manganese(III) and iron(III) is presented. The selective formation of the dinuclear complexes [M2(-salmp)2], M = Mn (1a), Fe (2a), [M2(-salmen)2(-OR)2)], R = Et, Me, H and M = Mn (3a–c) or Fe (4a–c), and (M2(-sal[p-X]ben)2(-OMe)2), X = tBu, Me, H, F, Cl, CF3, NO2 and M = Mn (5a–g) or Fe (6a–g), could be identified by reaction of the Schiff bases with metal salts and the base NEt3, and their characterization through elemental analysis, infrared spectroscopy, mass spectrometry and single-crystal X-ray diffraction of 2a2AcOEt, 2a2CH3CN and 3c2DMF was performed. In the case of iron(III) and H3salmp, when using NaOH as a base instead of NEt3, the dinuclear complexes [Fe2(-salmp)(-OR)(salim)2], R = Me, H (2b–c) could be isolated and spectroscopically characterized, including the crystal structure of 2b1.5H2O, which showed that rupture of one salmp3– to two coordinated salim– ligands and release of one salH molecule occurred. The same hydrolytic tendency could be identified with sal(p-X)ben ligands in the case of iron(III) also by using NEt3 or upon standing in solution, while manganese(III) did not promote such a C–N bond breakage. Cyclic voltammetry studies were performed for 3b, 4b, 5a and 6a, revealing that the iron(III) complexes can be irreversibly reduced to the mixed-valence FeIIFeIII and FeII2 dinuclear species, while the manganese(III) derivatives can be reversibly oxidized to either the mixed-valence MnIIIMnIV or to the MnIV2 dinuclear species. The super-exchange interaction between the metal centers, mediated by the bridging ligands, resulted in being antiferromagnetic (AFM) for the selected dinuclear compounds 3b, 4b, 5a, 5e, 5f, 6a and 6e. The coupling constants J (–2J Ŝ1·Ŝ2 formalism) had values around –13 cm–1 for manganese(III) compounds, among the largest AFM coupling constants reported so far for dinuclear MnIII2 derivatives, while values between –3 and –10 cm–1 were obtained for iron(III) compounds.

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