Halide Coordination of Perhalocyclohexasilane Si6X12 (X = Cl or Br)
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- 作者：Xuliang Dai ; Seok-Bong Choi ; Christopher W. Braun ; Pooja Vaidya ; Svetlana Kilina ; Angel Ugrinov ; Douglas L. Schulz ; Philip Boudjouk
- 刊名：Inorganic Chemistry
- 出版年：2011
- 出版时间：May 2, 2011
- 年：2011
- 卷：50
- 期：9
- 页码：4047-4053
- 全文大小：931K
- 年卷期：v.50,no.9(May 2, 2011)
- ISSN：1520-510X
文摘
The addition of halide anions (X鈥?= Cl鈭?/sup>, Br鈭?/sup>, or I鈭?/sup>) to perhalocyclohexasilane Si6X12 (X = Cl or Br) led to the formation of complexes comprising [Si6X12X鈥?sub>2]2鈭?/sup> dianions. An upfield shift in the 29Si NMR spectra was noted upon coordination, and structural determination by X-ray crystallography showed that the dianions adopt an 鈥渋nverse sandwich鈥?structure where the six cyclic silicon atoms form a planar hexagon with the two halide anions X鈥?located on the 6-fold axis equally disposed above and below the plane of the Si6 ring. Additionally, these apical X鈥?atoms are within the van der Waals bonding distance to the silicon ring atoms, indicating a strong interaction between X鈥?and silicon atoms. These results detail crystallographic variations within the halogen series providing further insight into the nature of the Lewis acid sites above and below the Si6X12 ring, where interactions with hard Lewis bases such as halide anions are observed. Interestingly, the stereochemistry of the silicon atoms in [Si6X12X鈥?sub>2]2鈭?/sup> is not affected much by the size or electronegativity of the halogen atoms.