Spin-crossover in coordination compounds of iron(II) with tris(pyrazol-1-yl)methane and cluster anions

Synthesis procedures for new coordination compounds of iron(II) with tris(pyrazol-1-yl)methane (HC(pz)(3)), containing cluster anions in the outer sphere, of the composition [Fe{HC(pz)(3)}(2)][Mo6Cl14]aEuro cent 2H(2)O (I), [Fe{HC(pz)(3)}(2)][Mo6Br14]aEuro cent H2O (II), and [Fe{HC(pz)(3)}(2)](2)[Re6S8(CN)(6)]aEuro cent 2H(2)O (III) are developed. The compounds are studied by static magnetic susceptibility, electronic, IR, and Mossbauer spectroscopic methods. The magnetochemical study shows that in the polycrystalline phases of all compounds the spincrossover (1) D (1) a double dagger" (5) D cent (2) is observed which is accompanied by thermochromism.