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)<sub>3</sub>), containing cluster anions in the outer sphere, of the composition [Fe{HC(pz)<sub>3</sub>}<sub>2</sub>][Mo<sub>6</sub>Cl<sub>14</sub>]×2H<sub>2</sub>O (I), [Fe{HC(pz)<sub>3</sub>}<sub>2</sub>][Mo<sub>6</sub>Br<sub>14</sub>]×H<sub>2</sub>O (II), and [Fe{HC(pz)<sub>3</sub>}<sub>2</sub>]<sub>2</sub>[Re<sub>6</sub>S<sub>8</sub>(CN)<sub>6</sub>]×2H<sub>2</sub>O (III) are developed. The compounds are studied by static magnetic susceptibility, electronic, IR, and Mössbauer spectroscopic methods. The magnetochemical study shows that in the polycrystalline phases of all compounds the spin-crossover <sup>1</sup> А <sub>1</sub> Û <sup>5</sup> - <sub>2</sub> is observed which is accompanied by thermochromism.