Electrochemical oxidation of benzyl germatranes

The electrooxidation of ring-substituted bromobenzylgermatranes in CH3CN and DMF solutions was studied. By cyclic voltammetry supported by DFT B3LYP/6-311G calculations, donor activity of the nitrogen atom was shown to be substantially reduced because of the dative N → Ge coordination compared to Et3N and (HOCH2CH2)3N. In the electrochemical context, the transmission of electronic effects between the ArCH2 moiety and the reaction center (the lone pair of N pointed inside the atrane cage) is well described by the generalized additive inductive model including mesomeric interactions. The oxidation process follows classical scheme for tertiary amines – reversible electron transfer with the ensuing deprotonation of α-carbon atom; at low scan rates the process is reversible/quasi-reversible and at higher rates it is under electron transfer control. Anodic cyanation of m-bromobenzylgermatrane was performed.