GAS-PHASE GERMYLATION OF SIMPLE AROMATICS BY ME3GE+ IONS

The germylation of simple aromatic hydrocarbons has been studied by tw o different techniques. The Fourier Transform Ion Cyclotron Resonance (FTICR) technique allowed the study of Me3Ge+ transfer equilibria betw een aromatics and H2O at 300 K. The ion-molecule reaction of [Me3Ge+. arene] ions with selected neutrals are accounted for by a a-complex sp ecies, retaining the primary ipso structure, where the germyl group an d the former aromatic hydrogen are bound to the same tetrahedral carbo n. The free energies of binding of Me3Ge+ to the selected aromatic com pounds correlate linearly with the values of the corresponding Me3Sireaction with a slope of 0.93. The combined information from the FTICR and radiolytic technique has revealed a mechanistic pattern for the e lectrophilic aromatic substitution by Me3Ge+ that closely reproduces t he corresponding Me3Si+ reaction, the major difference lying in the gr eater ease of detachment of Me3Ge+ by nucleophilic assistance. (C) 199 7 Elsevier Science S.A.