Four linear Cu II 3 subunit-based coordination polymers with various inter-subunit connections, spin ground-states and intra-/inter-subunit magnetic couplings

作者：En‐Cui Yang, Zhong‐Yi Liu, Si‐Hang Chen, Yan-Hong Su, Yanyan Zhang, Xiao‐Jun Zhao · 发表于：Dalton Transactions · 年份：2014 · DOI：10.1039/c4dt03741c · 被引用次数：14 · 研究领域：Metal-Organic Frameworks: Synthesis and Applications、Magnetism in coordination complexes、Lanthanide and Transition Metal Complexes

Four new 4-amino-1,2,4-triazole (atr)-based coordination polymers, {[Cu2(atr)(H2O)(μ-OH)2(pa)]·H2O}n (), {[Cu3(atr)2(H2O)2(μ-OH)2(npa)2]·2H2O}n (), {[Cu3(atr)5(dca)(μ-OH)(ClO4)2](ClO4)2}n () and {[Cu3(atr)2(H2O)(μ3-OH)(μ-OH)2(spa)]·1.5H2O}n () (pa(2-) = phthalate, npa(2-) = 3-nitrophthalate, dca(-) = dicyanamide and spa(3-) = 4-sulfophthalate), were successfully obtained by varying the carboxylate- and cyanide-modified magnetic bridges. Structural determinations reveal that the former three samples are bent one-dimensional chains constructed from linear Cu(II)3 subunits and different inter-subunit connections. In , linear {Cu3(μ-N1,N2-atr)2(μ-OH)2}(4+) and {Cu3(μ-COO)2(μ-OH)2}(4+) subunits are alternately connected in a sharing-vertex manner to give a ferrimagnetic S = 1/2 spin ground-state. The linear {Cu3(μ-N1,N2-atr)2(μ-OH)2}(4+) building block of is repeatedly bridged by pairs of single-atom bridging carboxylate groups of the npa(2-) ligand leading to a paramagnetic S = 1/2 spin ground-state. By contrast, each linear {Cu3(μ-N1,N2-atr)4}(6+) core in is periodically propagated by four-fold heterobridges (μ-OH(-), μ-ClO4(-), μ-N1,N2-atr and μ-dca(-)) to generate an overall diamagnetic S = 0 spin ground-state. Complex is a three-dimensional pillared-layer framework composed of linear {Cu3(μ-N1,N2-atr)2(μ-OH)2}(4+)-based layers and ditopic spa(3-) connectors, which exhibits a ferrimagnetic S = 1/2 spin ground-state and a metamagnetic transition resulting from the competition b...