2,2,6,6-Tetra-kis(biphenyl-2-yl)-4,4,8,8-tetramethylcyclotetrasiloxane

The title compound, [-Si(C₁₂H₉) ₂OSi(CH₃)₂O-]₂, was obtained unintentionally as the product of an attempted crystallization of caesium bis-(biphenyl-2,2′-di-yl)fluoro-silicate from dimethyl-formamide. In the crystal, the mol-ecule is located on an inversion center and the siloxane ring adopts a twist-chair conformation with the two dimethyl-substituted Si atoms lying 0.7081 (5) Å out of the plane defined by the two bis-(biphenyl-2-yl)-substituted Si atoms and the four O atoms. In each Si(C ₁₂H₉)₂ unit, the orientation of one terminal phenyl ring relative to the phenyl-ene ring of the other biphenyl moiety suggests a parallel displaced π-π stacking inter-action [centroid distance = 4.2377 (11) Å and dihedral angle = 15.40 (9)°].