Electronically switchable compounds constitute a wide family of very promising systems, especially in the field of data storage at a molecular scale. Amongst these compounds, cobalt-iron Prussian blue analogues (AxCoFe PBAs) are inorganic polymers based on Co-N≡C-Fe linkages that may exhibit two CoII(HS)-N≡C-FeIII(LS) and CoIII(LS)-N≡C-FeII(LS) (HS: high spin; LS: low spin) electronic states with very different structural and electronic properties. Electronic transition in between these two states can be reversibly controlled by a large variety of both chemical (insertion of alkali cations) and physical (temperature, pressure, irradiation) parameters. These photo switching properties are extremely appealing for the development of optical memory devices at the molecular scale.In order to understand the electronic properties of AxCoFe PBAs, the interaction occurring between the metallic centres through the cyanide bridge in the Co-N≡C-Fe linkages was investigated both at an experimental (use of synchrotron-radiation-based analytic techniques) and a theoretical (post-Hartree-Fock ab initio modelling) levels. The nature of the experimentally-demonstrated interaction between the alkali cations and the bimetallic network, made of the Co-N≡C-Fe linkages, was also studied. Finally, the relevance of the two-state model, usually invoked to account for the electronic properties of switchable systems, is discussed, as multistabilities are evidenced in PBAs. This work therefore offers study of the electronic phenomena occurring in such systems as comprehensive as possible.
