A benzene-rich pseudopolymorph of bis-[μ-1,3-bis-(penta-fluoro-phen-yl) prop-ane-1,3-dionato]-K³ O,O′:O′;K³ O:O,O′-bis-{aqua[1,3-bis-(penta-fluoro-phen-yl)propane-1,3-dionato-K ² O,O′]nickel(II)} benzene tetra-solvate

The title complex comprises two Ni²⁺ ions, four fluorinated ligands and two water mol-ecules in a centrosymmetric dinuclear complex. This compound was crystallized from benzene-CH₂Cl₂, and two types of crystals, viz. the title benzene tetra-solvate, [Ni₂(C ₁₅HF₁₀O₂)₄(H₂O) ₂]·4C₆H₆, (I), and the previously reported benzene disolvate, [Ni₂(C₁₅HF₁₀O ₂)₄(H₂O)₂]·2C ₆H₆, (II) [Hori et al. (2009). Bull. Chem. Soc. Jpn, 82, 96-98], were obtained as pseudopolymorphs. In the crystal structure of (I), the four benzene solvent mol-ecules inter-act closely with all the penta-fluoro-phenyl groups of the complex through arene-perfluoro-arene inter-actions. The mol-ecular structures of the two compounds show essentially the same conformation, although the benzene mol-ecules are accommodated in a columnar packing in (I), while they are isolated from each other in (II).