Synthesis of Low-Valent Dinuclear Group 14 Compounds with Element-Element Bonds by Transylidation.

Dinuclear low-valent compounds of the heavy main group elements are rare species owing to their intrinsic reactivity. However, they represent desirable target molecules due to their unusual bonding situations as well as applications in bond activations and materials synthesis. The isolation of such compounds usually requires the use of substituents that provide sufficient stability and synthetic access. Here we report on the use of strongly donating ylide-substituents to access low-valent dinuclear group 14 com-pounds. The ylides not only impart steric and electronic stabilization, but also allow facile synthesis via transfer of an ylide from tetrylene precursors of type R Y 2 E to ECl2 (E = Ge, Sn; Y = TolSO 2 (PR 3 )C with R = Ph, Cy). This method allowed the isolation of dinuclear complexes amongst a germanium analogue of a vinyl cation, [( Ph Y) 2 GeGe( Ph Y)]+ with an electronic struc-ture best described as a germylene-stabilized Ge(II) cation and a ylide(chloro)-digermene [ Ph Y(Cl)GeGe(Cl) Ph Y] with an unusually unsymmetrical structure.