Isolation and Reactivity of a Digerma Analogue of Vinyllithiums: a Lithium Digermenide

The versatile reactivity of disilenides, heavier analogues of vinyl anions, opened the door to novel heavier group 14 structure motifs with residual functionalities in the periphery around the Si═Si moiety. The corresponding germanium analogue, digermenide Tip2Ge═Ge(Tip)Li·dme2 (Tip = 2,4,6-triisopropylphenyl, dme = 1,2-dimethoxyethane), has now been obtained from the reduction of Tip2GeCl2 with 3.3 equiv of Li powder and a catalytic amount of naphthalene in dme at −70 °C. The lithium digermenide was characterized by NMR spectroscopy, UV/vis spectroscopy, X-ray diffraction, and DFT calculations. As proof of principle for its suitability for the nucleophilic transfer of the Ge═Ge motif, the reaction with chlorosilanes leads to the unsymmetrically substituted digermenes Tip2Ge═Ge(Tip)SiR3.