Design and characterization of Fe(II) complexes with tetradentate ligands exhibiting spin-crossover near room temperature.

Construction of spin-crossover (SCO) materials is very appealing for applications such as molecular switches and information storage. This study focuses on the design of Fe(II) complexes using ,'-bis(2-pyridinylmethyl)-1,2-ethanediamine-based ligands with an N4 structure for SCO material development. By incorporating -substituted benzene groups into the ligand's pyridine moiety, two polymorphs, α and β, were obtained, both exhibiting SCO activity.