Guo Jiajia, Cao Wenli, Li Shuailei, Miao Kanghua, Song Jirong, Huang Jie
Department of Chemical Engineering, Northwest University/Shaanxi Key Laboratory of Physico-Inorganic Chemistry, Xi'an, Shaanxi 710069, People's Republic of China.
Acta Crystallogr C Struct Chem. 2016 Feb;72(Pt 2):166-9. doi: 10.1107/S2053229616001509. Epub 2016 Jan 27.
The crystal engineering of coordination polymers has aroused interest due to their structural versatility, unique properties and applications in different areas of science. The selection of appropriate ligands as building blocks is critical in order to afford a range of topologies. Alkali metal cations are known for their mainly ionic chemistry in aqueous media. Their coordination number varies depending on the size of the binding partners, and on the electrostatic interaction between the ligands and the metal ions. The two-dimensional coordination polymer poly[tetra-μ-aqua-[μ4-4,4'-(diazenediyl)bis(5-oxo-1H-1,2,4-triazolido)]disodium(I)], [Na2(C4H2N8O2)(H2O)4]n, (I), was synthesized from 4-amino-1H-1,2,4-triazol-5(4H)-one (ATO) and its single-crystal structure determined. The mid-point of the imino N=N bond of the 4,4'-(diazenediyl)bis(5-oxo-1H-1,2,4-triazolide) (ZTO(2-)) ligand is located on an inversion centre. The asymmetric unit consists of one Na(+) cation, half a bridging ZTO(2-) ligand and two bridging water ligands. Each Na(+) cation is coordinated in a trigonal antiprismatic fashion by six O atoms, i.e. two from two ZTO(2-) ligands and the remaining four from bridging water ligands. The Na(+) cation is located near a glide plane, thus the two bridging O atoms from the two coordinating ZTO(2-) ligands are on adjacent apices of the trigonal antiprism, rather than being in an anti configuration. All water and ZTO(2-) ligands act as bridging ligands between metal centres. Each Na(+) metal centre is bridged to a neigbouring Na(+) cation by two water molecules to give a one-dimensional [Na(H2O)2]n chain. The organic ZTO(2-) ligand, an O atom of which also bridges the same pair of Na(+) cations, then crosslinks these [Na(H2O)2]n chains to form two-dimensional sheets. The two-dimensional sheets are further connected by intermolecular hydrogen bonds, giving rise to a stabile hydrogen-bonded network.
配位聚合物的晶体工程因其结构的多样性、独特的性质以及在不同科学领域的应用而引起了人们的兴趣。选择合适的配体作为结构单元对于获得一系列拓扑结构至关重要。碱金属阳离子在水介质中主要以离子化学而闻名。它们的配位数取决于结合伙伴的大小以及配体与金属离子之间的静电相互作用。二维配位聚合物聚[四-μ-水合-[μ4-4,4'-(二氮烯二基)双(5-氧代-1H-1,2,4-三唑基)]二钠(I)，[Na2(C4H2N8O2)(H2O)4]n，(I)，由4-氨基-1H-1,2,4-三唑-5(4H)-酮(ATO)合成，并测定了其单晶结构。4,4'-(二氮烯二基)双(5-氧代-1H-1,2,4-三唑化物)(ZTO(2-))配体的亚氨基N=N键的中点位于一个对称中心上。不对称单元由一个Na(+)阳离子、半个桥连ZTO(2-)配体和两个桥连水配体组成。每个Na(+)阳离子通过六个O原子以三角反棱柱的方式配位，即两个来自两个ZTO(2-)配体，其余四个来自桥连水配体。Na(+)阳离子位于一个滑移面附近，因此来自两个配位ZTO(2-)配体的两个桥连O原子位于三角反棱柱的相邻顶点上，而不是处于反式构型。所有的水和ZTO(2-)配体都作为金属中心之间的桥连配体。每个Na(+)金属中心通过两个水分子与相邻的Na(+)阳离子桥连，形成一维[Na(H2O)2]n链。有机ZTO(2-)配体，其一个O原子也桥连同一对Na(+)阳离子，然后交联这些[Na(H2O)2]n链形成二维片层。二维片层通过分子间氢键进一步连接，形成一个稳定的氢键网络。
