Spin crossover behavior of a tetranuclear iron(II) grid complex with a hydroxyl-group functionalized multidentate ligand

A tetranuclear iron grid-type spin crossover complex, [FeII4(HL)4](BF4)4·6H2O (1) (H2L = 2-(4-hydroxyphenyl)-4,5-bis{6-(3,5-dimethylpyrazol-1-yl)pyrid-2-yl}-1H-imidazole), was synthesized. Magnetic susceptibility measurements revealed that 1 showed gradual spin crossover behavior above 200 K. The electronic states were elucidated by Mössbauer spectra. [Display omitted] •Switchable molecules based on spin crossover phenomena.•Construction of a supramolecular [2 × 2] grid type complex by self-assembly.•Systematic studies on polynuclear spin crossover complexes.•Control of electronic states of iron ions by modification of substituent groups of the ligands. A tetranuclear iron grid-type spin crossover complex, [FeII4(HL)4](BF4)4·6H2O (1) (H2L = 2-(4-hydroxyphenyl)-4,5-bis{6-(3,5-dimethylpyrazol-1-yl)pyrid-2- yl}-1H-imidazole), was synthesized. Magnetic susceptibility measurements revealed that 1 shows gradual spin crossover behavior above 200 K. The electronic states of the compound were elucidated by Mössbauer spectra.