Co-ligand-directed structural and magnetic diversities in an anisotropic Co(II)-triazolate system.
Co-ligand-directed structural and magnetic diversities in an anisotropic Co(II)-triazolate system.
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DOI：
10.1039/c1dt10394f
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发表时间：
2011-08
影响因子：
4
通讯作者：
E. Yang;Zhong-Yi Liu;Tian-yu Liu;Li-Ly Li-Li-Ly-Li-2107969604;Xiao‐Jun Zhao
中科院分区：
文献类型：
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作者：
E. Yang;Zhong-Yi Liu;Tian-yu Liu;Li-Ly Li-Li-Ly-Li-2107969604;Xiao‐Jun Zhao
采用不同的含羧酸共配体合成了3种新型3,5-二氨基-1,2,4-三唑（Hdatrz）基Co（II）配合物[Co(Hdatrz)(0.5)(H(2)O)(2)(btec)(0.5)](n) (1), {[Co(Hdatrz)(Hbtc)]·H(2)O}(n)(2)和[Co(2)(datrz)(2)(nb)(2)](n) (3) （H（4)btec = 1,2,4,5-苯四羧酸，H(3)btc = 1,3,5-苯三羧酸和Hnb = 4-硝基苯甲酸）），并对其进行了结构和磁表征。配合物1是由中性μ(2)- n1， N4-Hdatrz配体支撑的波纹状Co(II)-btec（4-）层组成的三维柱状结构。另外两种配合物为手性(4,4)-和外消旋(4,8(2))-拓扑层，其中2种为双单齿Hbtc（2-）配体延伸的非对称μ(2)- n1， n4 - hdatrz桥接螺旋链，3种为μ(3)- n1, N2, N4-datrz（(-)）聚集的Shastry-Sutherland磁层。更有趣的是，观察到不同的磁现象，1为反铁磁有序态，2为T(N)小于2.0 K的自旋倾斜反铁磁态，3为自旋受挫和自旋翻转跃迁并存。是由各向异性Co(II)-三氮酸盐体系中羧酸盐和/或三氮酸盐异质桥介导的局部低维磁性基序控制的。
Three novel 3,5-diamino-1,2,4-triazole (Hdatrz)-based Co(II) coordination complexes, [Co(Hdatrz)(0.5)(H(2)O)(2)(btec)(0.5)](n) (1), {[Co(Hdatrz)(Hbtc)]·H(2)O}(n) (2) and [Co(2)(datrz)(2)(nb)(2)](n) (3) (H(4)btec = 1,2,4,5-benzenetetracarboxylic acid, H(3)btc = 1,3,5-benzenetricarboxylic acid and Hnb = 4-nitrobenzoic acid), were synthesized by incorporating different carboxylate-containing co-ligands and then were structurally and magnetically characterized. Complex 1 is a 3D pillared-layer framework with corrugated Co(II)-btec(4-) layers supported by neutral μ(2)-N1, N4-Hdatrz ligands. In contrast, the other two complexes are chiral (4, 4)- and racemic (4, 8(2))-topological layers with asymmetric μ(2)-N1, N4-Hdatrz-bridged helical chains extended by bis-monodentate Hbtc(2-) ligands for 2 and with a μ(3)-N1, N2, N4-datrz((-)) aggregated Shastry-Sutherland magnetic layer for 3. More interestingly, different magnetic phenomena with a field-induced metamagnetic transition from antiferromagnetic ordering to a ferromagnetic state for 1, spin-canted antiferromagnetism with a T(N) lower than 2.0 K for 2, as well as the coexistence of spin frustration and spin-flop transitions for 3 were observed, which, significantly, are governed by the local low-dimensional magnetic motifs mediated by the carboxylate and/or triazolate heterobridges in the anisotropic Co(II)-triazolate system.