Permethylated metallocenes as suitable models for the preparation of onium mono- and dications

Permethylated metallocenes of the iron subgroup (M = Fe, Ru, Os) have been considered as suitable models for preparing onium mono- and dications. EHM MO calculations of the charge, distribution in monocations of the type (C₅Me₅MC₅Me₄CH₂)⁺, homoannular dications of the type C₅Me₅MC₅Me₃(CH₂)₂]²⁺, and heteroannular dications of the type (C₅Me₄CH₂)₂M)]²⁺ indicate that the positive charge is mostly localized at the metal atom (M = Ru, Os and, to a lesser degree, Fe). This fact was confirmed by X-ray structural studies and the data of IR,¹H, and¹³C NMR spectroscopy, and electrochemistry. The reactivity of the monocations, in particular, interconversion of the odd-electron (17- and 19-electron) metallocenium radical cations and 18-electron metallocenyl carbocations has been studied. A M-C() -bond (M = Ru, Os) is realized in the mono- and dications. It has been suggested that the metallocenyl carbocations (M = Ru, Os) are in fact metallonium or metallocenonium cations (or dications).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1701–1709, October, 1994.We are grateful to the Uussian Ministry of Science and Technical for its Grant.