Simultaneous Fluoride Binding to Ferrocene-Based Heteronuclear Bidentate Lewis Acids

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• 作者：Ramez Boshra ; Krishnan Venkatasubbaiah ; Ami Doshi ; Roger A. Lalancette ; Lazaros Kakalis ; Frieder J&auml ; kle
• 刊名：Inorganic Chemistry
• 出版年：2007
• 出版时间：November 26, 2007
• 年：2007
• 卷：46
• 期：24
• 页码：10174 - 10186
• 全文大小：261K
• 年卷期：v.46,no.24(November 26, 2007)
• ISSN：1520-510X

文摘

A series of ₂-fluoro-bridged heteronuclear bidentate Lewis acid complexes [K(18-crown-6)THF]⁺ [Fc(BMeF)(SnMe₂Cl)F]^-(1-2F), [K(18-crown-6)THF]⁺ [Fc(BMeF)(SnMe₂F)F]^- (1-3F), [K(18-crown-6)THF]⁺ [Fc(BMePh)(SnMe₂Cl)F]^- (2-F),and [K(18-crown-6)THF]⁺ [Fc(BMePh)(SnMe₂F)F]^- (2-2F) (Fc = 1,2-ferrocenediyl) was prepared. Compounds 2-Fand 2-2F were obtained as a mixture of diastereomers, which arise due to the generation of a stereocenter atboron in addition to their inherent planar chirality. All compounds have been studied in the solid state by single-crystal X-ray diffraction analysis and by multinuclear NMR spectroscopy in solution. As a result of bridging-fluorideinteractions, tetrahedral boron and distorted trigonal-bipyramidal tin centers are observed. Comparison with thecorresponding monofunctional ferrocenylborates further supports the bridging nature of the fluoride anion. Two-dimensional exchange spectroscopy ¹⁹F NMR studies provide evidence for facile intermolecular and intramolecularfluorine exchange processes. All complexes display reversible one-electron oxidation events at lower potentialsthan those of the tricoordinate ferrocenylborane precursors, which is typical of ferrocenylborate complexes.