Creation of spin switching in graphene oxide-based hybrid film materials with an anionic Fe(iii) 5Cl-salicyaldehyde–thiosemicarbazone complex

Abstract

The present article describes the synthesis of hybrid composite film materials formed during the self-assembly process through non-covalent interactions of graphene oxide (GO) nanosheets with salt 1, represented by an anionic spin-crossover complex [Fe^III(5Cl-thsa)₂]⁻ (5Cl-thsa – 5-chlorosalicylaldehyde thiosemicarbazone) and the organic tetraethylammonium cation [Et₄N]⁺. The insertion of the salt 1 molecules into the interlayer space of GO nanosheets with the subsequent formation of a hybrid material GO–1 was observed. The film of the hybrid material GO–1 was characterized by scanning electron and confocal laser microscopy, EDX and XPS analysis, IR, Raman and ⁵⁷Fe Mössbauer spectroscopy, dc magnetic measurements, and powder X-ray diffraction. Comparison of the magnetic properties of salt 1 and a film of the hybrid material GO–1 demonstrated a significant influence of the GO nanosheets matrix on the completeness of spin transition and showed a slight shift of the hysteresis loop by 1 K in the temperature range of 200–230 K. DFT calculations showed an important role of the organic cation [Et₄N]⁺ in the process of adsorption of the spin-crossover anion [Fe^III(5Cl-thsa)₂]⁻ on the GO nanosheet surface.