Four Novel Metal Diphosphonate Compounds Based on 2-(1-Triazole)-1-Hydroxyl-1,1′-Ethylidenediphosphonic Acid: Syntheses, Topological Structures, and Magnetic Properties

Hydrothermal reactions of Mn(II), Cu(II), Co(II), and Ni(II) salts with 2-(1-triazole)-1-hydroxyl-1,1′-ethylidenediphosphonic acid (tahedpH4) lead to four novel metal phosphonates, namely, Mn2(tahedp)(H2O)2 (1), Cu2(tahedp)(H2O) (2), Co(tahedpH2) (3) and Ni2(tahedpH2)2·(NH2CH2CH2NH2) (4). In compound 1, dimeric units {Mn12O2} are linked together by the O3−P1−O1 groups forming an inorganic chain. The adjacent chains are further connected by {Mn2O4N} pentahedra to form an undulating inorganic layer. The inorganic layers are bridged by the triazole groups resulting in a three-dimensional framework structure. In the opinion of the topology, the structure of 1 can be described as an unprecedented trinodal (4.66.83)2(42.62.82)(5.62)2 topological network. Compound 2 shows a pillared layered structure in which the {Cu12O2} dimers are linked together by the O3−P1−O1 groups forming a double chain. The double chains and the {−Cu2−O5−P2−O4−}2 eight-membered rings are further linked through the coordination of O2 and O6 atoms into a layer. The neighboring layers are connected together by the triazole rings, resulting in a pillared layered structure. Topological analysis of compound 2 reveals that it is a unique 3, 4, and 5-connected net with (42.6)2(42.84)(43.6.86)2 topology. Compound 3 exhibits a layer structure made up of Co2(tahedpH2)2 dimer units. Compound 4 exhibits a layer architecture that built from {NiO5N} octahedra interconnected by phosphonate groups and triazole rings. Magnetic measurements reveal that antiferromagnetic interactions are mediated between magnetic centers in all four compounds.

以二价锰(Mn(II))、二价铜(Cu(II))、二价钴(Co(II))和二价镍(Ni(II))盐与2-(1-三唑基)-1-羟基-1,1'-亚乙基二膦酸（tahedpH4）进行水热反应，得到四种新型金属膦酸盐，分别为Mn₂(tahedp)(H₂O)₂（1）、Cu₂(tahedp)(H₂O)（2）、Co(tahedpH₂)（3）以及Ni₂(tahedpH₂)₂·(NH₂CH₂CH₂NH₂)（4）。在化合物1中，二聚单元{Mn₁₂O₂}通过O3−P1−O1基团相互连接形成无机链；相邻无机链进一步经由{Mn₂O₄N}五配位多面体连接，构筑出起伏的无机层；该无机层通过三唑基团桥联，最终形成三维骨架结构。从拓扑学角度分析，化合物1的结构可被描述为一种前所未有的三节点(4.6⁶.8³)₂(4₂.6₂.8₂)(5.6²)₂拓扑网络。化合物2呈现柱层状结构，其中{Cu₁₂O₂}二聚体通过O3−P1−O1基团连接形成双链；该双链与{−Cu₂−O5−P2−O4−}₂八元环进一步通过O2、O6原子的配位作用连接为层状结构；相邻层通过三唑环相互连接，最终形成柱层状结构。对化合物2的拓扑分析表明，其为一种独特的3、4、5连接网络，具有(4₂.6)₂(4₂.8₄)(4₃.6.8₆)₂拓扑构型。化合物3展现出由Co₂(tahedpH₂)₂二聚单元构成的层状结构。化合物4呈现由{NiO₅N}八面体通过膦酸基团与三唑环相互连接构筑的层状骨架结构。磁性测量结果显示，四种化合物的磁中心之间均存在反铁磁相互作用。