Solvent-dependent SCO Behavior of Dinuclear Iron(II) Complexes with a 1,3,4-Thiadiazole Bridging Ligand

Two dinuclear iron­(II) complexes [Fe₂(μ-L)₂]­X₄*4DMF (X = BF₄^– (1·4DMF) and ClO₄^– (2·4DMF)) with a 1,3,4-thiadiazole bridging ligand have been synthesized and show a very distinct solvent-depending SCO behavior. The complexes represent new solvatomorphs of the first dinuclear iron­(II) complexes with the ligand L (2,5-bis­[(2-pyridylmethyl)­amino]­methyl-1,3,4-thiadiazole). The incorporated lattice DMF molecules directly affect the spin state of these complexes. This behavior reveals a structural insight into the role of the solvent molecules on the spin transition.