文摘
We show a marked tendency of Fe(II) to form heteroleptic [Fe(L)(L′)](ClO<sub>4sub>)<sub>2sub> complexes from pairs of chelating tris-imine 3bpp, tpy, or 2bbp ligands. New synthetic avenues for spin crossover research become thus available, here illustrated with three new heteroleptic compounds with differing magnetic behaviors: [Fe(H<sub>4sub>L1)(Cl-tpy)](ClO<sub>4sub>)<sub>2sub>·C<sub>3sub>H<sub>6sub>O (1), [Fe(H<sub>2sub>L3)(Me3bpp)](ClO<sub>4sub>)<sub>2sub>·C<sub>3sub>H<sub>6sub>O (2), [Fe(H<sub>4sub>L1)(2bbp)](ClO<sub>4sub>)<sub>2sub>·3C<sub>3sub>H<sub>6sub>O (3). Structural studies demonstrate that 1 is in the low-spin (LS) state up to 350 K, while complexes 2 and 3 are, by contrast, in the high-spin (HS) state down to 2 K, as corroborated through magnetic susceptibility measurements. Upon exposure to the atmosphere, the latter exhibits the release of three molecules of acetone per complex, turning into the solvent-free analogue [Fe(H<sub>4sub>L1)(2bbp)](ClO<sub>4sub>)<sub>2sub> (3a), through a single-crystal-to-single-crystal transformation. This guest extrusion process is accompanied by a spin switch, from HS to LS.