Frontispiece: Hypervalent Pentafluoroethylgermanium Compounds, [(C2F5)nGeX5-n]- and [(C2F5)3GeF3]2- (X=F, Cl; n=2-5)

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Salts with pentacoordinated germanate anions are quite rare. In their Full Paper, B. Hoge et al. present the synthesis of (bacterio-)FAGes. For example, the fluoro(perfluoroalkyl)germanate [(C2F5)3GeF2]- was generated nearly quantitatively by the treatment of (C2F5)3GeNEt2 with anhydrous HF. Quantum chemical calculations of the fluoride-ion affinity revealed (C2F5)3PF2 as a stronger Lewis acid than (C2F5)3GeF. The pentafluoroethylation reaction of [(C2F5)3GeF2]- furnished the tetrakis(pentafluoroethyl)fluorogermanate [(C2F5)4GeF]-, whereby the pentakis(pentafluoroethyl)germanate ion [Ge(C2F5)5]- was observed as a thermolabile initial product, releasing C2F4 at approximately 20 C to form the final product [(C2F5)4GeF]-.