Insertion Reaction of Me₃SiN₃ with Bis(germylene)

Herein, we describe the redox reaction of bis(germylene) PhC(NBu)₂Ge-Ge(NBu)₂CPh with different equivalents of Me₃SiN₃ affording two distinct products. The reaction of Me₃SiN₃ with bis-germylene in a 1:1 molar ratio results in compound 1 at -78 °C; however, treatment of bis-germylene with a 2.1 equiv of Me₃SiN₃ at room temperature results in compound 2. The formation of 1 and 2 can be rationalized by two successive 3 + 1 cycloadditions of Me₃SiN₃ with the germanium center of bis(germylene) and N₂ elimination. All of the compounds are well-characterized by various spectroscopic techniques and single-crystal X-ray structural analyses. Density functional theory (DFT) calculations suggest that compound 2 has a dicoordinated nitrogen atom, which is stabilized by hyperconjugative interactions, resulting in pseudo-germylimine moiety. However, the dicoordinated nitrogen atom shows high basicity as indicated by proton affinity values. These are rare examples of isolated products that show insertion as well as simultaneous redox properties of bis(germylene).