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

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)center dot(18-crown-6)(0.5)center dot 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 P (1) over bar 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, alpha=77.894 0(10)degrees, beta=78.877 0(10)degrees, gamma=88.684 0(10)degrees. 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.