Key Laboratory of Inorganic-Organic Hybrid Functional Material Chemistry, Ministry of Education, Tianjin Key Laboratory of Structure and Performance for Functional Molecules, College of Chemistry, Tianjin Normal University, Tianjin 300387, P. R. China.
Dalton Trans. 2013 Nov 28;42(44):15716-25. doi: 10.1039/c3dt52190g.
Three extended three-dimensional (3D) magnetic metal-organic frameworks (MMOFs), {[Mn3(H2O)2(atz)4Cl2]·2CH3OH}n (1), {[Mn2(H2O)(atz)2(ip)]·C2H5OH}n (2) and {[Mn2(H2O)2(atz)(btc)]·3H2O·0.7CH3OH}n (3) (atz(-) = 5-aminotetrazolate, ip(2-) = isophthalate and btc(3-) = 1,3,5-benzenetricarboxylate), were respectively obtained by varying the coligands with different numbers of functionalities and molecular topology, and structurally and magnetically characterized. Complex 1 exhibits an eight-connected 3(6)·4(18)·5(3)·6 topological network with linear Mn(II)3 subunits periodically linked by ditopic atz(-) connectors. Complex 2 possesses a pillared-layer framework constructed from undulated {Mn2(atz)2} layers and bidirectional ip(2-) spacers. By contrast, 3 consists of bent one-dimensional (1D) {Mn(atz)} ribbons, which are crosslinked through the carboxylate groups of tripodal btc(3-) connectors to generate a 3D architecture. Structural analysis reveals that the interesting motifs of 1-3 and their diverse linkages are significantly dominated by the cooperate coordination of the mixed ligands to the octahedral Mn(II) ion. Magnetically, 1 displays ferrimagnetic behavior resulting from the periodic arrangement of the net moment in the Mn(II)3 subunit, which is scarcely observed in the homometallic azolate systems. Complex 2 features unusual coexistence of spin-canted antiferromagnetic behavior and field-induced spin-flop transition due to the asymmetric magnetic superexchange within the two-dimensional (2D) {Mn2(atz)2} sublayer. By contrast, only antiferromagnetic ordering is observed in the 1D {Mn(atz)} ribbon of 3. These interesting results suggest that the diverse structural motifs by the cooperate coordination of octahedral Mn(II) ion with the N-rich tetrazolyl group can more significantly direct the magnetic behaviors and could be hopefully utilized upon the construction of novel MMOFs.
三个扩展的三维（3D）磁性金属有机骨架（MMOF），[{Mn3（H2O）2（atz）4Cl2]·2CH3OH}n（1），[{Mn2（H2O）（atz）2（ip）]·C2H5OH}n（2）和[{Mn2（H2O）2（atz）（btc）]·3H2O·0.7CH3OH}n（3）（atz（-）= 5-氨基四唑，ip（2-）= 间苯二甲酸根和 btc（3-）= 1,3,5-苯三甲酸根），分别通过改变具有不同功能和分子拓扑结构的共配体来获得，并进行了结构和磁性表征。配合物 1 表现出八连接的 3（6）·4（18）·5（3）·6拓扑网络，其中线性 Mn(II)3 亚基周期性由双齿 atz（-）连接器连接。配合物 2 具有由波纹状{Mn2（atz）2}层和双向 ip（2-）间隔物构建的支柱层状框架。相比之下，3 由弯曲的一维（1D）{Mn（atz）} 带组成，这些带通过三脚架 btc（3-）连接器的羧基交联，生成三维结构。结构分析表明，1-3 的有趣结构基元和它们的不同连接方式主要由混合配体对八面体 Mn(II)离子的协同配位决定。磁性方面，1 表现出亚铁磁性行为，这是由于 Mn(II)3 亚基中的净磁矩周期性排列所致，这种行为在同金属唑体系中很少见。配合物 2 由于二维（2D）{Mn2（atz）2} 亚层内不对称的磁超交换作用，表现出异常的自旋倾斜反铁磁行为和场诱导自旋翻转转变。相比之下，在 3 的一维{Mn（atz）} 带中仅观察到反铁磁有序。这些有趣的结果表明，八面体 Mn(II)离子与富 N 的四唑基的协同配位所产生的不同结构基元可以更显著地影响磁行为，并有望用于构建新型 MMOFs。
