Crystal Engineering, Growth and Design Laboratory, Department of Chemistry, University of Crete, Voutes Campus, Crete, GR-71003, Greece.
Inorg Chem. 2012 Jul 16;51(14):7889-96. doi: 10.1021/ic300941t. Epub 2012 Jun 29.
In this paper we report the synthesis and structural characterization of the 2D layered coordination polymer Mg(BPMGLY)(H(2)O)(2) (BPMGLY = bis-phosphonomethylglycine, (HO(3)PCH(2))(2)N(H)COO(2-)). The Mg ion is found in a slightly distorted octahedral environment formed by four phosphonate oxygens and two water molecules. The carboxylate group is deprotonated but noncoordinated. This compound is a useful starting material for a number of topotactic transformations. Upon heating at 140 °C one (of the two) Mg-coordinated water molecule is lost, with the archetype 2D structure maintaining itself. However, the octahedral Mg in Mg(BPMGLY)(H(2)O)(2) is now converted to trigonal bipyramidal in Mg(BPMGLY)(H(2)O). Upon exposure of the monohydrate Mg(BPMGLY)(H(2)O) compound to ammonia, one molecule of ammonia is inserted into the interlayer space and stabilized by hydrogen bonding. The 2D layered structure of the product Mg(BPMGLY)(H(2)O)(NH(3)) is still maintained, with Mg now acquiring a pseudo-octahedral environment. All of these topotactic transformations are also accompanied by changes in hydrogen bonding between the layers.
在本文中，我们报告了二维层状配位聚合物 Mg(BPMGLY)(H(2)O)(2)（BPMGLY = 双膦酸甲基甘氨酸，(HO(3)PCH(2))(2)N(H)COO(2-))的合成和结构表征。Mg 离子位于由四个磷酸根氧和两个水分子形成的略微扭曲的八面体环境中。羧酸根被去质子化但不配位。该化合物是许多拓扑转化的有用起始材料。在 140°C 加热时，一个（两个中的一个）Mg 配位水分子失去，原型二维结构保持不变。然而，Mg(BPMGLY)(H(2)O)(2)中的八面体 Mg 现在转化为 Mg(BPMGLY)(H(2)O)中的三角双锥。当将一水合物 Mg(BPMGLY)(H(2)O)化合物暴露于氨时，一个氨分子插入层间空间并通过氢键稳定。产物 Mg(BPMGLY)(H(2)O)(NH(3))的二维层状结构仍然保持，Mg 现在获得了拟八面体环境。所有这些拓扑转化都伴随着层间氢键的变化。
