Synthesis of a crystalline functional material based on an aminopyridine-type cobalt thiocyanate complex and characterization of its dielectric-ferroelectric properties

• Published in: Journal of molecular structure 2024-05, Vol.1304, p.137661, Article 137661
• Main Authors: Lv, Mei-xia, Yang, Fang, Yan, Yi-bo, Hu, Hong-zhi, Liu, Yang, Liu, Zun-qi
• Format: Article
• Language: English
• Subjects: Dielectric property; Ferroelectric property; Hydrogen bond; Thiocyanate complex; Variable-temperature infrared
• ISSN: 0022-2860
• DOI: 10.1016/j.molstruc.2024.137661

•A hybrid crystalline material (C5H7N2)3[Co(SCN)4]Cl obtained by evaporation method.•The smallest structural units formed 1D chain and 2D mesh structures.•Pendulum motion of cations led to a significant obvious of the hydrogen-bonded chain.•The anisotropic and ferroelectric properties were determined in the compound.•This provides useful strategies of finding new ferroelectric/dielectric materials. A hybrid organic-inorganic crystalline material, (C5H7N2)3[Co(SCN)4]Cl (1), was obtained from 3-aminopyridine, hexaaquacobalt(II) chloride, ammonium thiocyanate, and hydrochloric acid in a mixed solvent of methanol and water by using the evaporation method. Variable-temperature infrared spectroscopy, single crystal X-ray diffraction (XRD), powder XRD, thermogravimetric analysis, variable-temperature and -frequency dielectric constant measurement, ferroelectric testing, and other tests were performed to investigate the structure and properties of compound 1. The results showed that at both low and room temperatures, the formed crystals were orthorhombic and belonged to the P212121 polar space group. The smallest structural units of the crystal formed one-dimensional chain and two-dimensional mesh structures through N—H···Cl and N—H···S hydrogen bonds. With the change in temperature, the random and pendulum motion of the cations of 3-aminopyridine led to a significant elongation of the hydrogen-bonded chain at the a-axis direction, resulting in the observed anisotropic and ferroelectric properties of compound 1. [Display omitted]