Structure and Bonding of KSiH3 and Its 18-Crown-6 Derivatives: Unusual Ambidentate Behavior of the SiH3鈥?/sup> Anion

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• 作者：David J. Wolstenholme ; Paul D. Prince ; G. Sean McGrady ; Michael J. Landry ; Jonathan W. Steed
• 刊名：Inorganic Chemistry
• 出版年：2011
• 出版时间：November 7, 2011
• 年：2011
• 卷：50
• 期：21
• 页码：11222-11227
• 全文大小：818K
• 年卷期：v.50,no.21(November 7, 2011)
• ISSN：1520-510X

文摘

Density functional theory (DFT) calculations of [K(18-crown-6)SiH₃] (1) and KSiH₃ (2) have shown that both the classical tet and non-classical inv coordination modes of the [SiH₃]^{鈭?/sup> anion to the K+ ion are energetically accessible. Single-crystal X-ray structures of the tet and inv derivatives [K(18-crown-6)SiH₃路THF] (1a) and [K(18-crown-6)SiH₃路HSiPh₃] (1b) confirm this conclusion, showing that small changes in the coordination sphere of the metal are sufficient to alter the orientation of the anion. A topological analysis of the calculated electron densities for 1 and 2 reveals that the K路路路Si interaction in the tet conformer of 2 possesses a significant amount of covalent character. In contrast, the inv form of 2 displays primarily electrostatic character for the K路路路Si and K路路路H interactions. Incorporation of the 18-crown-6 ligand in 1 reduces the polarizing power of the K+ cation, hardening the cation鈥揳nion interaction in both conformers. The experimental structures of 1a and 1b bear out these conclusions, with the strongly bound tetrahydrofuran (THF) ligand softening the K+ ion in 1a and favoring the tet conformer, while the weakly interacting HSiPh₃ ligand in 1b has minimal effect on the K+ center, resulting in an inv orientation.}