Magnetic Study on a Two-Dimensional Coordination Polymer with Mixed Bridging Ligands

Abstract

A two-dimensional coordination polymer, [Co(μ_1,3-SCN)₂(μ_1,6-dmpzdo)]_n (where dmpzdo = 2,5-dimethylpyrazine-1,4-dioxide), has been synthesized and its crystal structure determined by X-ray crystallography. In the complex, the adjacent Co(II) ions are coordinated by μ_1,3-SCN^- bridging ligands which forms a one-dimensional chain along the a axis; the one-dimensional chains are further connected by μ_1,6-dmpzdo bridging ligands which leads to the formation of a two-dimensional layer on the ac plane. The theoretical calculations reveal that a ferromagnetic coupling exists between the μ_1,3-SCN^- bridging Co(II) ions and an anti-ferromagnetic interaction between the μ_1,6-dmpzdo bridging Co(II) ions, and the anti-ferromagnetic interaction is stronger than the ferromagnetic interaction. The fitting of the variable-temperature (34−300 K) magnetic susceptibilities reveals that there is an anti-ferromagnetic coupling between the bridging Co(II) ions with the magnetic coupling constant J = −3.52 cm^-1.