Four coordination polymers of different transition metal ions with a new pyridyl-dicarboxylate ligand, 4-(3,5-dicarboxylphenyl)-2-methylpyridine (H₂L), were synthesized under solvothermal conditions and their structures and properties were characterized. They are formulated as [Zn(L)(H₂O)]·H₂O (1), [Mn₃(L)₂Cl₂(H₂O)₂]·2H₂O (2), [Co₃(L)₂(NO₃)₂(H₂O)₂] (3) and [Ni₃(L)₂(NO₃)₂(H₂O)₂]] (4). Compound 1 exhibits a 2D network with a (3,6)-connected kgd topology based on the dinuclear [Zn₂O₂] units. In compound 2, the linear trinuclear [Mn₃(μ-O_carboxylate)₂(COO)₂Cl₂] units with mixed carboxylate and μ-Cl triple bridges are cross-linked by the L ligands into a 3D framework with a (3,6)-connected rtl topology. Compounds 3 and 4 are isostructural and both show 2D networks in which the linear trinuclear [M₃(μ-O_carboxylate)₂(COO)₂(μ-O_NO3)₂] units (M = Co (3) and Ni (4)) are cross-linked by the L ligands. Compound 1 shows strong blue emissions in the solid state at room temperature. Magnetic studies indicate that the mixed triple [(μ-O_carboxylate)(COO)Cl] bridges transmit antiferromagnetic interactions between Mn(II) ions in 2, while the mixed triple (μ-O_carboxylate)(COO)(μ-O_NO3) bridges in 3 and 4 transmit ferromagnetic interactions. Further magnetic studies demonstrated that the Co(II) compound shows no long-range magnetic ordering at 2 K.

中文翻译：

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四种基于双核和三核单元的配位聚合物，具有新的多功能吡啶基-二羧酸酯配体：发光和磁性

在溶剂热条件下合成了具有新型吡啶基-二羧酸酯配体4-（3,5-二羧基苯基）-2-甲基吡啶（H ₂ L）的四种不同过渡金属离子的配位聚合物，并对其结构和性能进行了表征。它们被配制为[Zn（L）（H ₂ O）]·H ₂ O（1），[Mn ₃（L）₂ Cl ₂（H ₂ O）₂ ]·2H ₂ O（2），[Co ₃（L）₂（NO ₃）₂（H ₂ O）₂ ]（3）和[Ni ₃（L）₂（NO ₃）₂（H ₂ O）₂ ]]（4）。化合物1表现出基于双核[Zn ₂ O ₂ ]单元的具有（3,6）连接的kgd拓扑的2D网络。在化合物2中，具有混合羧酸盐和μ-Cl三桥的直链三核[Mn ₃（μ-O_羧酸盐）₂（COO）₂ Cl ₂ ]单元通过L配体交联成具有（3 ，6）-连接的rtl拓扑。化合物3和4是同构的，都显示二维网络，其中线性三核[M ₃（μ-O_羧酸盐）₂（COO）₂（μ- _{ONO 3}）₂ ]单元（M = Co（3）和Ni（4）通过L配体交联。化合物1在室温下在固态下显示出很强的蓝色发射。磁性研究表明，混合的三重[[μ-O_羧酸盐）（COO）Cl]桥可传输2中的Mn（II）离子之间的反铁磁相互作用，而混合的三重[μ-O_羧酸盐）（COO）（μ- _{ONO 3}）中的3和4桥传输铁磁相互作用。进一步的磁性研究表明，Co（II）化合物在2 K下没有长距离的磁性排序。