One-Dimensional Manganese Coordination Polymers Composed of Polynuclear Cluster Blocks and Polypyridyl Linkers: Structures and Properties

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• 作者：Svetlana G. Baca ; Iurii L. Malaestean ; Tony D. Keene ; Harry Adams ; Michael D. Ward ; Jü ; rg Hauser ; Antonia Neels ; Silvio Decurtins
• 刊名：Inorganic Chemistry
• 出版年：2008
• 出版时间：December 1, 2008
• 年：2008
• 卷：47
• 期：23
• 页码：11108-11119
• 全文大小：473K
• 年卷期：v.47,no.23(December 1, 2008)
• ISSN：1520-510X

文摘

The synthesis, crystal structures and magnetic properties of five new manganese compounds are reported. These include a linear trinuclear cluster [Mn(II)₃(O₂CCHMe₂)₆(dpa)₂]·2MeCN (1) (dpa = 2,2′-dipyridylamine), a tetranuclear cluster [Mn(II)₂Mn(III)₂O₂(O₂CCMe₃)₆(bpy)₂] (3) (bpy = 2,2′-bipyridine), and chain coordination polymers composed of cluster blocks such as Mn₃, Mn₃O, and Mn₄O₂ bridged by 2,2′-bipyrimidine (bpm) or hexamethylentetramine (hmta) ligands to give ([Mn(II)₃(O₂CCHMe₂)₆(bpm)]·2EtOH)_n (2), [Mn(II)₂Mn(III)₂O₂(O₂CCHMe₂)₆(bpm)(EtOH)₄]_n (4), and (([Mn(II)Mn(III)₂O(O₂CCHMe₂)₆(hmta)₂]·EtOH)_n (5). The magnetic analysis of the compounds was achieved using a combination of vector coupling and full-matrix diagonalization methods. Susceptibility data for compound 1 was fitted using a vector coupling model to give g = 2.02(1) and 2J/k_B = −5.38(2) K. To model the trimer chain, we used vector coupling for initial values of J₁ and then diagonalization techniques to estimate J₂ to give g = 1.98(1), 2J₁/k_B = −3.3(1) K and 2J₂/k_B = −1.0(1) K by approximating the system to a dimer of trimers. The analysis of 3 was made difficult by the mixture of polymorphs and the difficulties of a three-J model, while for 4 an analysis was not possible because of the size of the computation and the relative magnitudes of the three couplings. Compound 5 was modeled using the same techniques as 2 to give g = 1.99(1), 2J₁/k_B = +32.5(2) K, 2J₂/k_B = −16.8(1) K, and 2J₃/k_B = +0.4(1) K. The combination of techniques has worked well for compounds 2 and 5 and thus opens up a method of modeling complex chains.