Mn4 Single-Molecule-Magnet-Based Polymers of a One-Dimensional Helical Chain and a Three-Dimensional Network: Syntheses, Crystal Structures, and Magnetic Properties

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• 作者：Hui-Lien Tsai ; Chen-I Yang ; Wolfgang Wernsdorfer ; Siang-Hua Huang ; Siang-Yu Jhan ; Ming-Hsuan Liu ; Gene-Hsiang Lee
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：December 17, 2012
• 年：2012
• 卷：51
• 期：24
• 页码：13171-13180
• 全文大小：618K
• 年卷期：v.51,no.24(December 17, 2012)
• ISSN：1520-510X

文摘

Two Mn₄ single-molecule-magnet (SMM)-based coordination polymers, {[Mn₄O(salox)₃(N₃)₃(DMF)₂(H₂O)(dpp)]路0.5MeOH}_n (1路0.5MeOH; H₂salox = salicylaldoxime; dpp = 1,3-di-4-pyridylpropane; DMF = N,N-dimethylformamide) and {[Mn₄O(Me-salox)₃(N₃)₃(dpp)_1.5]路1.5Et₂O}_n (2路1.5Et₂O; Me-H₂salox = hydroxyphenylethanone oxime), are self-assembled from Mn(ClO₄)₂路6H₂O/H₂salox and Mn(ClO₄)₂路6H₂O/Me-H₂salox systems with dpp and NaN₃ in DMF/MeOH, respectively. Both compounds comprise a mixed-valence tetranuclear manganese core, [Mn^IIMn^III₃O]⁹⁺, which serves as a building unit for subsequent assembly via oximate and azido ligands. The flexible dpp ligand links with a Mn₄ unit, leading to the formation of a one-dimensional helical structure in 1路0.5MeOH and a three-dimensional pcu network in 2路1.5Et₂O. The magnetic data analysis shows that antiferromagnetic interactions within the Mn₄ units resulted in S = ³/₂ and ⁷/₂ ground states for 1路0.5MeOH and 2路1.5Et₂O, respectively. Both compounds show SMM behavior, as evidenced by frequency-dependent out-of-phase signals in alternating-current magnetic susceptibility and magnetic hysteresis loop studies with an energy barrier of U_eff = 37 K for 2路1.5Et₂O.