Received 5 December 2012
The title compound, C28H52Si8, was synthesized by condensation of two molecules of 1,2,3,4-tetrakis(chlorodimethylsilyl)benzene with lithium. The 3,4-disila-1,2-benzocyclobutene rings in the centrosymmetric molecule are bridged by 1,1,2,2-tetramethyldisilanylene chains with an anti conformation. The benzene rings are deformed by fusion with a 3,4-disilacyclobutene ring resulting in a slight boat conformation. Two Si-C bonds are bent to reduce the steric repulsion between the methyl groups on the two Si atoms and the methyl groups on another two Si atoms.
For structures of cyclophanes bridged by tetramethyldisilanylene chains, see: Sakurai et al. (1986); Sekiguchi et al. (1989).
Data collection: CrystalClear (Rigaku, 2003); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: SHELXL97 and Yadokari-XG 2009 (Kabuto et al., 2009).
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: DS2224 ).
This work was supported in part by Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan and the Japan Society for the Promotion of Science. This work was also supported by the Element Innovation Project of Gunma University.
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