氰基合钴(Ⅲ)氢键型笼状超分子晶体的合成、结构及介电性质

Synthesis, Structure and Dielectric Properties of Cyanide Cobalt(Ⅲ) Hydrogen-Bonding Cage-like Supramolecular Crystal

以2-氯苯胺(o-chloroaniline,o-CA)、18-冠醚-6(18-crown-6)和钴氰酸为原料,在甲醇和水的混合溶液内通过蒸发法合成氰基合钴配合物氢键笼状超分子晶体材料(H)0.5(o-CAH)[Co(CN)6]0.5·(18-crown-6)0.5·H_2O (1)。并通过单晶X射线衍射、红外光谱、粉末X射线衍射、元素分析、热重分析(TG)和介电常数测试等对超分子晶体进行了结构及电性能表征。测试结果表明,该晶体在低温下属于三斜晶系,空间群为P1,晶胞参数为a=0.869 22(1) nm,b=0.964 09(12) nm,c=1.129 93(14) nm,α=77.894 0(10)°,β=78.877 0(10)°,γ=88.684 0(10)°。结构显示氰基合钴配合物、超分子阳离子和水分子通过氢键相互作用在空间内形成三维笼状。笼状顶点的钴原子随着温度的变化其间距发生明显的伸缩,导致晶体在260 K附近观察到明显的介电异常现象。

Using o-chloroaniline (o-CA), 18-crown-6 and cobalt cyanide as reactant, a small-molecule metal complex (H)0.5(o-CAH)[Co(CN)6]0.5·(18-crown-6)0.5·H2O (1) was synthesized by evaporation in the mixed solution of methanol and water. The structure and electrical properties of 1 were characterized by single crystal X-ray diffraction, infrared spectroscopy, thermogravimetric analysis (TG) and dielectric measurements. The results showed that 1 crystalizes in the triclinic system with the space group P1 at low-temperature (100 K). The cell parameters are as follows: a=0.869 22(1) nm, b=0.964 09(12) nm, c=1.129 93(14) nm,α=77.894 0(10)°,β= 78.877 0(10)°,γ=88.684 0(10)°. Single crystal X-ray diffraction show a three-dimensional cage-like structure through hydrogen bonds of cyanide cobalt, supramolecular cations and water molecules. When the temperature changed, the space between the cobalt atoms of the cage-like vertex showed significant stretching deformation, which resulted in the distinct dielectric anomaly observed around 260 K. CCDC: 1858374, LT, 1858375, RT.