A base-stabilized germavinylidene

Germavinylidenes (R₂C=Ge), the heavier congeners of vinylidenes, have long remained elusive, both as free species and in Lewis base-stabilized forms. Herein, we report the isolation of a base-stabilized germavinylidene employing an imine-functionalized cyclic (alkyl)(amino)carbene (imino-CAAC) ligand. Comprehensive structural characterization, supported by theoretical calculations, confirms the presence of a Ge=C double bond, with the divalent germanium center coordinated by the imine donor. Preliminary reactivity studies reveal a rich chemical profile: the complex undergoes selective methylation at the germanium center, forms a π-dominated coordination complex with iron carbonyl, and acts as a germanium atom transfer reagent to generate a rare tetraazagermylene. Furthermore, a [2 + 2] cycloaddition with isocyanate provides compelling evidence for the Ge=C double bond character. These results underscore the previously unexplored potential of imino-CAAC ligands in stabilizing reactive and uncharted p-block main group species.