Crystal structure and magnetic properties of bis­[butyl­tris­(1H-pyrazol-1-yl)borato]iron(II)

The asymmetric unit of the title compound, [Fe(C13H18BN6)2], contains two half independent complex mol­ecules. In each complex, the FeII atom is located on an inversion center and is surrounded by two scorpionate ligand butyl­tris­(1H-pyrazol-1-yl)borate mol­ecules that coordinate to the iron(II) ion through the N atoms of the pyrazole groups. The two independent complex mol­ecules differ essentially in the conformation of the butyl substituents. In the crystal, the complex mol­ecules are linked by a series of C—H⋯π inter­actions, which generate a supra­molecular three-dimensional structure. At 120 K, the average Fe—N bond distance is 1.969 A, indicating the low-spin state of the iron(II) atom, which does not change upon heating, as demonstrated by high-temperature magnetic susceptibility measurements.