Oligogermanes Containing Only Electron-Withdrawing Substituents: Synthesis and Properties

A series of germanes Ar3GeX, containing electron-withdrawing substituents [Ar = p-FC6H4, 1a-d, 1a (X = CO, 1b (X = Br), 1c (X = H), 1d (X = NMe2); p-F3CC6H4, 2a-d, 2a (X = Cl), 2b (X = Br), 2c (X = H), 2d (X = NMe2)], was synthesized and used to prepare symmetrical digermanes Ar3Ge-GeAr3, (p-FC6H4)(3)GeGe(C6H4F-p)(3) (3), and (p-F3CC6H4)(3)GeGe(C6H4CF3-p)(3) (4) and trigermane [(p-F3CC6H4)(3)Ge](2)Ge(C6F5)(2) (5) by hydrogermolysis reaction. The properties of all compounds were investigated by multinuclear NMR and for oligogermanes by UV/vis and fluorescence spectroscopy, as well as by electrochemical methods. In addition, the molecular structures of 1a, 1b, 2b, 2c, and 3-5 were studied by X-ray diffraction analysis. Compound 5 showed a significantly shifted UV/visible absorption to the red field in comparison with previously described derivatives.