Synthesis and crystal structure of the low-spin iron(II) complex [Fe(bpz)3](ClO4)2 · H2O (bpz=2,2′-bipyrazine)

The crystal structure of the title compound [Fe(bpz)3](ClO4)2 · H2O (bpz=2,2′-bipyrazine) has been determined by a single crystal X-ray diffraction study at 293(2) K. The complex is monoclinic, P21/c, a=17.263(3), b=9.983(2), c=17.921(4) Å, β=107.94(3)°, V=2938.3(10) Å3, Z=4, R=0.073 and Rw=0.118. The structure is made up of tris-chelated [Fe(bpz)3]2+ cations, uncoordinated perchlorate anions and crystallization water molecules. The iron atom exhibits a FeN6 distorted octahedral geometry with average Fe–N bond length and N–Fe–N bidentate angle of 1.962(5) Å and 81.6(2)°. The value of the Fe–N bond distance and that of the room temperature magnetic moment are in agreement with a singlet 1A1 ground state. The structure of 1 is compared to those of other tris-chelated iron(II) complexes with bidentate nitrogen heterocycles.