A Cu(II) coordination polymer, [Cu2(pztrz)2(μ-CH3COO)(CH3COO)]·3H2O (1), derived from mono-substituted 1,2,4-triazole derivative 3-(pyrazinyl)-1,2,4-triazole (Hpztrz) is isolated and structurally characterized. X-ray structural analysis shows that Hpztrz ligands and acetate anions demonstrate different coordination modes in complex 1. The two Cu(II) ions are bridged by the 1,2,4-triazole ring of Hpztrz to form a dinuclear unit, which is further linked by two bridging acetate anions to form a tetranuclear Cu4 unit. Interestingly, each Cu4 unit is connected to another four Cu4 units through the outer pyrazinyl of Hpztrz, resulting in a two-dimensional (2D) layer structure. Consecutive layers are further packed into three-dimensional (3D) structures through interlayer hydrogen-bonding interactions. Furthermore, variable-temperature magnetic susceptibility studies reveal that the antiferromagnetic interactions are mediated through 1,2,4-triazole-N1,N2 bridges and acetate bridges with coupling constants of J1 = − 69.98 cm−1 and J2 = − 2.15 cm−1. Synergistic co-coordination of 1,2,4-triazole and acetate ions with Cu(II) ions led to a dinuclear unit, then to a Cu4 unit and finally to a 2D layer. Consecutive layers are further packed into a 3D framework through interlayer hydrogen-bonding interactions. Furthermore, variable-temperature magnetic susceptibility studies indicated the existence of antiferromagnetic coupling between the Cu(II) ions.

中文翻译：

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通过 1,2,4-三唑和乙酸根阴离子协同桥接形成的铜基配位聚合物：合成、晶体结构和磁性

Cu(II)配位聚合物，[Cu2(pztrz)2(μ-CH3COO)(CH3COO)]·3H2O(1)，衍生自单取代的1,2,4-三唑衍生物3-(吡嗪基)-1， 2,4-三唑 (Hpztrz) 已分离并具有结构特征。X射线结构分析表明，Hpztrz配体和乙酸根阴离子在配合物1中表现出不同的配位模式。两个Cu(II)离子通过Hpztrz的1,2,4-三唑环桥连形成双核单元，进一步由两个桥接乙酸根阴离子连接形成四核 Cu4 单元。有趣的是，每个 Cu4 单元通过 Hpztrz 的外吡嗪基连接到另外四个 Cu4 单元，从而形成二维（2D）层结构。通过层间氢键相互作用，连续层被进一步包装成三维 (3D) 结构。此外，变温磁化率研究表明，反铁磁相互作用是通过 1,2,4-三唑-N1,N2 桥和醋酸桥介导的，耦合常数为 J1 = − 69.98 cm−1 和 J2 = − 2.15 cm−1。1,2,4-三唑和乙酸根离子与 Cu(II) 离子的协同配位导致双核单元，然后是 Cu4 单元，最后是 2D 层。通过层间氢键相互作用，连续层被进一步打包成 3D 框架。此外，变温磁化率研究表明 Cu(II) 离子之间存在反铁磁耦合。1,2,4-三唑和乙酸根离子与 Cu(II) 离子的协同配位导致双核单元，然后是 Cu4 单元，最后是 2D 层。通过层间氢键相互作用，连续层被进一步打包成 3D 框架。此外，变温磁化率研究表明 Cu(II) 离子之间存在反铁磁耦合。1,2,4-三唑和乙酸根离子与 Cu(II) 离子的协同配位导致双核单元，然后是 Cu4 单元，最后是 2D 层。通过层间氢键相互作用，连续层被进一步打包成 3D 框架。此外，变温磁化率研究表明 Cu(II) 离子之间存在反铁磁耦合。