Chemistry and Chemical Engineering College, Xinjiang Agricultural University, Urumqi 830052, China.
Xinjiang Sub-Center National Engineering Research Center of Novel Equipment for Polymer Processing, Urumqi 830052, China.
Int J Mol Sci. 2024 Aug 21;25(16):9064. doi: 10.3390/ijms25169064.
By introducing disordered molecules into a crystal structure, the motion of the disordered molecules easily induces the formation of multidimensional frameworks in functional crystal materials, allowing for structural phase transitions and the realization of various dielectric properties within a certain temperature range. Here, we prepared a novel ionic complex [CHN][Fe(NCS)]HO () between 2-aminobenzimidazole and ferric isothiocyanate from ferric chloride hexahydrate, ammonium thiocyanate, and 2-aminobenzimidazole using the evaporation of the solvent method. The main components, the single-crystal structure, and the thermal and dielectric properties of the complex were characterized using infrared spectroscopy, elemental analysis, single-crystal X-ray diffraction, powder XRD, thermogravimetric analysis, differential scanning calorimetry, variable-temperature and variable-frequency dielectric constant tests, etc. The analysis results indicated that compound belongs to the 2/n space group. Within the crystal structure, the [Fe(NCS)] anion formed a two-dimensional hydrogen-bonded network with the organic cation through SS interactions and hydrogen bonding. The disorder-order motion of the anions and cations within the crystal and the deformation of the crystal frameworks lead to a significant reversible isostructural phase transition and multiaxial dielectric anomalies of compound at approximately 240 K.
通过向晶体结构中引入无序分子，无序分子的运动很容易在功能晶体材料中诱导形成多维框架，从而允许在一定温度范围内发生结构相变并实现各种介电性能。在这里，我们使用溶剂蒸发法，由六水合三氯化铁、硫氰酸铵和 2-氨基苯并咪唑制备了一种新型离子配合物[CHN][Fe(NCS)]HO()，它是 2-氨基苯并咪唑和铁异硫氰酸根之间的配合物。使用红外光谱、元素分析、单晶 X 射线衍射、粉末 XRD、热重分析、差示扫描量热法、变温和变频率介电常数测试等方法对配合物的主要成分、单晶结构、热性能和介电性能进行了表征。分析结果表明，化合物属于 2/n 空间群。在晶体结构中，[Fe(NCS)]阴离子通过 SS 相互作用和氢键与有机阳离子形成二维氢键网络。晶体中阴离子和阳离子的无序-有序运动以及晶体骨架的变形导致化合物在约 240 K 时发生显著的可逆同构相转变和多轴介电异常。
