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

Lanthanide-iron clusters usually display interesting structures and outstanding magnetic properties. However, due to the high reactivity (acidity) of the Fe 3+ -H 2 O 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 [Y 6 Fe(HL) 10 (NO 3 ) 2 (EG) 2 (μ 3 -OH) 8 (H 2 O) 4 ]·ClO 4 ·N-H 2 BDEA·2H 2 O ( Y 6 Fe , 1 , H 2 L = 3-hydroxypivalic acid, EG = ethylene glycol, N-H 2 BDEA = 2,2'-(butylimino)diethanol), [Ln 8 Fe 3 (H 2 TEOA) 2 (HTEOA) 2 (HL) 10 (μ 3 -OH) 9 (μ 2 -OH)(μ 4 -O) 2 (H 2 O) 4 ]·(NO 3 ) 3 · x H 2 O (Ln = Y, x = 13 for 2 , Y 8 Fe 3 ; Ln = Dy, x = 10 for 3 , Dy 8 Fe 3 ; H 3 TEOA = triethanolamine), and [Ln 12 Fe 14 (HL) 16 (μ 3 -OH) 20 (μ 2 -OH) 12 (μ 4 -O) 12 (H 2 O) 12 ]·(NO 3 ) 6 · x H 2 O (Ln = Y, x = 40 for 4 , Y 12 Fe 14 ; Ln = Dy, x = 30 for 5 , Dy 12 Fe 14 ) 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 1 - 5 . Compound 1 was formed by two {Y 3 Fe(μ 3 -OH) 4 } units with the common vertices, and compounds 2 and 3 were formed by two {Y 3 Fe(μ 3 -OH) 3 (μ 4 -O)} units with the common vertices bridging a quadrilateral unit {Ln 2 Fe 2 (μ 3 -OH) 3 (μ 2 -OH)}. The basic structural units of cubane-like {Ln 2 Fe 2 (μ 3 -OH)(μ 4 -O) 3 }, triangular {LnFe 2 (μ 3 -OH) 2 (μ 4 -O)}, and neutral iron-hydroxyl {Fe(μ 3 -OH)(μ 2 -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 1 - 5 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.