Substituent Effects in Digermanes: Electrochemical, Theoretical, and Structural Investigations

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• 作者：Erin K. Schrick ; Trevor J. Forget ; Kimberly D. Roewe ; Aaron C. Schrick ; Curtis E. Moore ; James A. Golen ; Arnold L. Rheingold ; Nicholas F. Materer ; Charles S. Weinert
• 刊名：Organometallics
• 出版年：2013
• 出版时间：April 8, 2013
• 年：2013
• 卷：32
• 期：7
• 页码：2245-2256
• 全文大小：538K
• 年卷期：v.32,no.7(April 8, 2013)
• ISSN：1520-6041

文摘

The digermanes R₃GeGePh₃ (R₃ = Buⁱ₃, Hexⁿ₃, (C₁₈H₃₇)₃, or Bu^tMe₂) were synthesized using the hydrogermolysis reaction, and the X-ray crystal structures of Buⁱ₃GeGePh₃and Bu^tMe₂GeGePh₃ were determined. The isobutyl-substituted digermane contains two independent molecules in the unit cell with Ge鈥揋e bond distances of 2.4410(5) and 2.4409(5) 脜, and Bu^tMe₂GeGePh₃ has a Ge鈥揋e bond distance of 2.4255(3) 脜. These four digermanes and the four additional digermanes R₃GeGePh₃ (R₃ = Me₃, Buⁿ₃, Bu^s₃, or PhMe₂) were characterized by cyclic voltammetry, differential pulse voltammetry, and linear sweep voltammetry in order to determine the effects of varying substituent patterns on the oxidation potential of these systems. Digermanes having more inductively donating substituents exhibit more negative oxidation potentials than those having less inductively donating substituents. Density functional theory calculations were also performed on these eight systems, and the energies of their frontier orbitals were determined. The energy of the HOMO and LUMO in these systems was shown to depend on the electron-donating ability of the organic substituents.