Wang Jingen, Huang Xihe, Huang Changcang, Song Haiyan, Yang Duoping
Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350002, People's Republic of China.
Acta Crystallogr C. 2007 Dec;63(Pt 12):m583-5. doi: 10.1107/S0108270107053292. Epub 2007 Nov 24.
In the title complex, poly[triaquabis(dimethylformamide)di-mu3-oxalato-mu2-oxalato-dilanthanum(III)], [La2(C2O4)3(C3H7NO)(H2O)3]n, both La ions are coordinated by nine O atoms, forming slightly distorted tricapped trigonal prisms. The two La ions, the terminal water O atom, and the O and N atoms of the dimethylformamide molecule reside on twofold rotation axes, giving the two La-centered coordination geometries twofold or pseudo-twofold symmetries. The two oxalate ligands, one of which rests on a center of inversion at the mid-point of the C-C bond, adopt different bridging modes, connecting with the La ions to form two types of lanthanide oxalate chains, i.e. anionic {[La(C2O4)2(DMF)(H2O)2]n-}(n) (DMF is dimethylformamide) and cationic zigzag {[La(C2O4)(H2O)]n+}n, respectively. Each zigzag cationic chain is linked to four adjacent anionic chains via the bridging oxalate anions, and each anionic chain connects with four zigzag cationic chains, constructing a three-dimensional neutral framework.
在标题配合物聚[三水双（二甲基甲酰胺）双-μ3-草酸根-μ2-草酸根-二镧（III）]，[La2(C2O4)3(C3H7NO)(H2O)3]n中，两个镧离子均由九个氧原子配位，形成略微扭曲的三帽三棱柱。两个镧离子、末端水分子的氧原子以及二甲基甲酰胺分子的氧原子和氮原子位于二重旋转轴上，使得两个以镧为中心的配位几何结构具有二重或准二重对称性。两个草酸根配体，其中一个位于碳-碳键中点的对称中心上，采用不同的桥连模式，与镧离子相连形成两种类型的镧系草酸根链，即阴离子型{[La(C2O4)2(DMF)(H2O)2]n-}(n)（DMF为二甲基甲酰胺）和阳离子型锯齿状{[La(C2O4)(H2O)]n+}n。每条锯齿状阳离子链通过桥连草酸根阴离子与四条相邻的阴离子链相连，且每条阴离子链与四条锯齿状阳离子链相连，构建出一个三维中性骨架。
