Angle-dependent spin crossover properties in polymorphic iron(ii) complexes based on pyridine–triazole derivatives

Abstract

Two new Fe(II) compounds based on a pyridine–triazole ligand with an NCS⁻ co-ligand were synthesized as thermodynamic (1) and kinetic (2) products. Single crystal X-ray diffraction evidenced that these compounds are polymorphs. The magnetic susceptibility of each compound was recorded, which showed that 1 undergoes a sharp spin crossover, while 2 remains in the high spin state across the temperature range. We discussed here the importance and impact of crystalline packing on the switching properties of these compounds.