Structural Correlations in High-Spin Complexes of [Fe{HC(3,5-Me2pz)3}2]2+: Solid State Structure of [Fe{HC(3,5-Me2pz)3}2][Fe2OCl6]

Abstract  The cation in the solid state structure of [Fe{HC(3,5-Me₂pz)₃}₂][Fe₂OCl₆] (pz = pyrazolyl ring) contains an octahedral iron(II) center with an average Fe–N bond distance of 2.17 Å, indicating that the iron(II) is in the high-spin form. While M–N bond distances of this length with κ³-[HC(3,5-Me₂pz)₃] ligands generally cause tilting of pz to open up the “bite” angle, in this structure the average tilting angle is only 3.1°, a much lower value than observed in earlier structures of this same cation paired with different anions. The crystals are monoclinic, space group P2₁/n, with a = 11.1671(12) Å, b = 10.8091(11) Å, c = 17.4385(17) Å, α = γ = 90°, β = 95.685(2)°, and Z = 2. Graphical Abstract  The cation in the solid state structure of [Fe{HC(3,5-Me₂pz)₃}₂][Fe₂OCl₆] (pz = pyrazolyl ring) contains an octahedral iron(II) center in the high-spin form with unusual orientations of the pyrazolyl rings.