Four 3,5-diamino-1,2,4-triazole-based cobalt(II/III) complexes incorporating with 5-substituted isophthalate coligands: Synthesis, structure and magnetism

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• 作者：Hong Zhao^a ; Hong-Xue Li^a ; Zhong-Yi Liu^a ; En-Cui Yang^a ; ^{encui_yang@163.com" class="auth_mail" title="E-mail the corresponding author} ; Xiao-Jun Zhao^a ; ^b ; ^{xiaojun_zhao15@163.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：3 ; 5-Diamino-1 ; 2 ; 4-triazole ; Substituted isophthalate ; Crystal structure ; Magnetism ; Coordination polymer
• 刊名：Polyhedron
• 出版年：2015
• 出版时间：24 November 2015
• 年：2015
• 卷：101
• 期：Complete
• 页码：29-36
• 全文大小：1990 K

文摘

Four 3,5-diamino-1,2,4-triazole (Hdatrz)-based cobalt(II/III) coordination polymers, {[Co₂(Hdatrz)(NH₂-ip)₂]·0.5H₂O}_n (boldFont">1), [Co(CH₃OH)(Hdatrz)(CH₃-ip)]_n (boldFont">2), {[Co₂(datrz)₂(CH₃-ip)]·2.5H₂O}_n (boldFont">3) and {[Co(datrz)(NO₂-ip)]·H₂O}_n (boldFont">4) (NH₂-ip²⁻ = 5-aminoisophthalate, CH₃-ip²⁻ = 5-methylisophthalate and NO₂-ip²⁻ = 5-nitroisophthalate), were hydro-/solvothermally synthesized by changing the substituents attached on the isophthalate coligand, which were structurally and magnetically characterized. Complex boldFont">1 is a corrugated layer with dimeric {Co₂(μ-N1,N2-Hdatrz)}⁴⁺ subunits extended by three-connected NH₂-ip²⁻ connectors. Constructed from the same mixed ligands, both boldFont">2 and boldFont">3 exhibit robust three-dimensional (3D) frameworks consisting of helical {Co(μ-N1,N4-Hdatrz)}²⁺ chain and corner-sharing triangular {Co₂(μ₃-N1,N2,N4-datrz)₂}²⁺ layer, respectively. By contrast, two bis-monodentate NO₂-ip²⁻ and two μ-N1,N4-datrz⁻ anions connect tetrahedral Co(III) sites into a (4, 4) grid-like layer of boldFont">4. Thus, the substituent of the isophthalate coligand is observed to virtually influence the overall structures of the resulting complexes by changing the binding modes of the coligand and coordination polyhedra. Additionally, complex boldFont">1 exhibits a metamagnetic transition from antiferromagnetic ordering to weak ferromagnetic state. Instead, typically antiferromagnetic interactions are respectively mediated by the cyclic triazolate ligand along the helical chain of boldFont">2 and in the distorted triangular layer of boldFont">3.