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Aminopolyol-Dependent Assembly of Heterometallic Lanthanide–Iron–Oxo Clusters

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journal contribution
posted on 2022-12-07, 21:06 authored by Shan-Shan Chen, Xiu-Ying Zheng, HaiQuan Tian, La-Sheng Long, Lan-Sun Zheng, Xiang-Jian Kong
Lanthanide–iron clusters usually display interesting structures and outstanding magnetic properties. However, due to the high reactivity (acidity) of the Fe3+–H2O bond and the inability to form a terminal oxo ligand, the preparation of high-nuclearity Ln–Fe clusters is a great challenge. Herein, a series of lanthanide–iron–oxo clusters with the formulas [Y6Fe(HL)10(NO3)2(EG)23-OH)8(H2O)4]·ClO4·N-H2BDEA·2H2O (Y6Fe, 1, H2L = 3-hydroxypivalic acid, EG = ethylene glycol, N–H2BDEA = 2,2′-(butylimino)diethanol), [Ln8Fe3(H2TEOA)2(HTEOA)2(HL)103-OH)92-OH)(μ4-O)2(H2O)4]·(NO3)3·xH2O (Ln = Y, x = 13 for 2, Y8Fe3; Ln = Dy, x = 10 for 3, Dy8Fe3; H3TEOA = triethanolamine), and [Ln12Fe14(HL)163-OH)202-OH)124-O)12(H2O)12]·(NO3)6·xH2O (Ln = Y, x = 40 for 4, Y12Fe14; Ln = Dy, x = 30 for 5, Dy12Fe14) were obtained by adjusting the pH with different aminopolyols as organic alkalis. Structural analysis showed that a cubane-like unit was the main structural unit in compounds 15. Compound 1 was formed by two {Y3Fe(μ3-OH)4} units with the common vertices, and compounds 2 and 3 were formed by two {Y3Fe(μ3-OH)34-O)} units with the common vertices bridging a quadrilateral unit {Ln2Fe23-OH)32-OH)}. The basic structural units of cubane-like {Ln2Fe23-OH)(μ4-O)3}, triangular {LnFe23-OH)24-O)}, and neutral iron–hydroxyl {Fe(μ3-OH)(μ2-OH)2} were found in compounds 4 and 5. The universality of building blocks for the assembly has been demonstrated in high-nuclearity lanthanide–iron–oxo clusters. Meanwhile, the structural regulation of the lanthanide–iron–oxo clusters 15 was realized by adjusting the pH with different organic alkalis, which provided the reference for the effective synthesis of high-nuclearity lanthanide–iron–oxo clusters. Magnetic studies showed that 3 and 5 displayed a slow magnetic relaxation behavior.

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