Dicationic 1‑Germaand 1‑Stannavinylidenes:Synthesis, Structure, and Reactivity

The synthesis of heteronuclear vinylidene analogues containing heavier group 14 elements (R₂CE:, E = Si, Ge, Sn) has been a challenging task due to their inherent instability. In this study, we report the synthesis of dicationic 1-germavinylidene (<b>3Ge</b>) and 1-stannavinylidene (<b>3Sn</b>) by using sym-bis(2-pyridyl)-tetraphenylcarbodiphosphorane (CDPPy₂) as a donor ligand. Both <b>3Ge</b> and <b>3Sn</b> have been characterized by single-crystal X-ray diffraction analysis, NMR spectroscopy, and high-resolution mass spectrometry. The structural analysis, supported by the results of theoretical calculations, confirms that <b>3Ge</b> and <b>3Sn</b> feature a polarized CE double bond and a lone pair of electrons located at the E atom (E = Ge and Sn). The reactions of <b>3Ge</b> with IDippMCl (M = Cu, Ag, Au) give the M–Cl bond addition products. Mechanistic studies on the activation of the Au–Cl bond by <b>3Ge</b> demonstrate its ambiphilicity. This work represents an example of the utilization of a carbone ligand as both an σ and π donor for the synthesis of heavier heteronuclear vinylidene analogues.