A series of new Fe(II) coordination polymers based-on [Hg(XCN)3]− or [Hg(XCN)4]2− (X = S, Se) building blocks: Synthesis, crystal structure and magnetic property

Self-assembly of the tetrahedral metalloligand building block [(HgII(XCN)4]2-, where X ​= ​S or Se, a series of bis-monodentate pyridine-like ligands and iron(II) compounds has afforded seven new heterobimetallic HgII–FeII coordination polymers. Single crystal X-ray diffraction structural analysis revealed the infinite two-dimensional (2D) sheet with different topologies for all the complexes except 3, which belonged to inherent 3D-structure. The results of the temperature dependent magnetic susceptibility investigation over all the complexes discovered the paramagnetic behavior for the high spin iron(II) ion in all the complexes within the temperature range of 2–300K, except complex 6. The thermo- and photomagnetic property study for complex 6 showed incomplete spin crossover (SCO) behaviors with interesting thermomagnetic properties and light-induced excited spin state trapping effect (LIESST). The results show that the ligand field, configurations, rigidity, and polarity of the bridging ligands, as well as the coordination mode with the Fe(II) ion of the building units, are important for the design and synthesis of the targeted coordination polymers.