Isolation and Reactivity of an Alkyl-Substituted Germanium(I) Radical Anion

The isolation of low-valent main group radical species remains a fundamental challenge in synthetic chemistry due to their intrinsic instability. Herein, we report the successful isolation and full characterization of an alkyl-substituted germanium(I) radical anion stabilized solely by steric protection, without electronic perturbations. This radical anion exhibits exceptional thermal stability in both solid state and solution at room temperature, enabling thorough structural, spectroscopic and reactivity investigations. EPR spectroscopy and DFT calculations consistently verify predominant localization of the unpaired electron at the germanium center. Furthermore, the Ge(I) radical anion presents unique radical reactivity patterns demonstrating by its reactivity investigation. This work establishes a new paradigm for synthesizing challenging low-valent main group radical species.