Co(II) single-ion magnets: synthesis, structure, and magnetic properties

Magnetoactive coordination compounds exhibiting bi- or multistability between two or more magnetic stable states present an attractive example of molecular switches. Currently, the research is focused on molecular nanomagnets, especially single molecule magnets (SMMs), which are molecules, where the slow relaxation of the magnetization based on the purely molecular origin is observed. Contrary to ferromagnets, the magnetic bistability of SMMs does not require intermolecular interactions, which makes them particularly interesting in terms of application potential, especially in the high-density storage of data. This paper aims to introduce the readers into a basic understanding of SMM behaviour, and furthermore, it provides an overview of the attractive Co(II) SMMs with emphasis on the relation between structural features, magnetic anisotropy, and slow relaxation of magnetization in tetra-, penta-, and hexacoordinate complexes.