Research Article: 1,1,4,4-Tetra-tert-butyl-1,4-dichloro-2,2,3,3-tetra­phenyl­tetra­silane

Date Published: February 01, 2012

Publisher: International Union of Crystallography

Author(s): Kyohei Otsuka, Shintaro Ishida, Soichiro Kyushin.


The title compound, C40H56Cl2Si4, was synthesized by the coupling of 1,1-di-tert-butyl-1,2-dichloro-2,2-diphenyl­disilane with lithium. The asymmetric unit contains one half-mol­ecule, which is completed by an inversion centre. In the mol­ecule, the tetra­silane skeleton adopts a perfect anti conformation and the Si—Si bonds [2.4355 (5) and 2.4328 (7) Å] are longer than the standard Si—Si bond length (2.34 Å). The Si—Si—Si angle [116.09 (2)°] is larger than the tetra­hedral bond angle (109.5°). These long bond lengths and the wide angle are favorable for reducing the steric hindrance among the tert-butyl and the phenyl groups. The dihedral angle between the phenyl rings in the asymmetric unit is 37.36 (8)°.

Partial Text

For details of Wurtz-type reactions for formation of silicon–silicon bonds, see: Burkhard (1949 ▶); Gilman & Tomasi (1963 ▶); Stolberg (1963 ▶); Laguerre et al. (1978 ▶); Herman et al. (1985 ▶); Watanabe et al. (1988 ▶). For related structures of oligosilanes with anti conformations, see: Baumeister et al. (1997 ▶); Michl & West (2000 ▶); Tsuji et al. (2004 ▶); Fukazawa et al. (2006 ▶); Haga et al. (2008 ▶).