A reversible metal-ligand bond break associated to a spin-crossover

The [(FeL)-L-II(CN)(2)]center dot H2O complex,dicyano[2,13-dimethyl-6,9-dioxa-3,12,18-triazabicyclo[12.3.1] octadeca-1(18), 2,12,14,16-pentaene]iron(II) monohydrate, exhibits a thermal induced metal-ligand bond break reversible in the solid state and associated to a spin crossover that corresponds to an unprecedented structurally characterized modification of the coordination metal environment from a hepta- coordinate high spin state to a hexa-coordinate low spin state.