Received 22 November 2012
The molecule in the structure of the title compound, C34H60Si4, lies on a twofold rotation axis that passes through the two Si atoms, resulting in a planar cyclotetrasilane ring. The dihedral angle between the cyclotetrasilane ring and the phenyl ring is 68.20 (5)°. The Si-Si bonds [2.4404 (8) and 2.4576 (8) Å] are longer than a standard Si-Si bond (2.34 Å) and the C-Si-C bond angle [97.07 (14)°] of the phenyl-substituted Si atom is smaller than the tetrahedral bond angle (109.5°). These long bonds and small bond angle are favorable for reducing the steric hindrance among the bulky substituents.
For background to and applications of phenyl-substituted oligosilanes, see: Hinch & Krc (1957); Matsumoto & Tanaka (2008). For a related structure of a cyclotetrasilane without phenyl groups, see: Kyushin et al. (1995).
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 (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: IS5224 ).
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.
Burla, M. C., Caliandro, R., Camalli, M., Carrozzini, B., Cascarano, G. L., De Caro, L., Giacovazzo, C., Polidori, G. & Spagna, R. (2005). J. Appl. Cryst. 38, 381-388.
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.
Hinch, R. J. & Krc, J. Jr (1957). Anal. Chem. 29, 1550-1551.
Jacobson, R. (1998). REQAB. Private communication to the Rigaku Corporation, Tokyo, Japan.
Kabuto, C., Akine, S., Nemoto, T. & Kwon, E. (2009). J. Crystallogr. Soc. Jpn, 51, 218-224.
Kyushin, S., Sakurai, H. & Matsumoto, H. (1995). J. Organomet. Chem. 499, 235-240.
Matsumoto, H. & Tanaka, R. (2008). Jpn Kokai Tokkyo Koho JP4132933.
Rigaku (2003). CrystalClear. Rigaku Corporation, Tokyo, Japan.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.