Spin switch in dinuclear cobalt dioxolene complexes and iron 1,3,4 thio/oxadiazole complexes

Molecular bistable systems, which can be reversible switched by external stimuli such as temperature, pressure, light or the chemical environment are at the forefront of next generation materials, including molecular-scale memory elements or adaptive sensors. Among molecular bistable systems, metal complexes featuring open-shell ions are particularly suited, as changes in their electronic structure can induce significant modifications in their physical properties. Two key classes of molecular bistable metal complexes exhibit this multi-stability: (i) valence tautomeric (VT) complexes and (ii) spin-crossover (SCO) complexes. Frequently only monomeric systems have been investigated, which limits their possible application due to the limit of possible accessible states. To overcome this and retaining the necessary chemical tuneability, dinuclear complexes are particular suited. They represent the smallest unit for two interacting spin centers for systematic investigation.