Synthesis and structure of the azidogermyliumylidene azide complex [L(N3)Ge:](+)N3- with covalently and ionically bonded azide ligands at germanium(II) [L = bis(N-heterocyclic carbene)].

Starting from the chlorogermyliumylidene chloride salt [L(Cl)Ge:]Cl (1) (L = 1,1'-methylene-3,3'-di-2,6-diisopropyl-phenylimidazole-2,2'-diylidene), the chloride ion can be easily substituted by BPh4 to yield [L(Cl)Ge:]BPh4 (3). Reaction of the latter with NaN3 furnishes [L(N3)Ge:]BPh4 (4). In contrast, the direct reaction of 1 with NaN3 affords exclusively the first azidogermyliumylidene azide salt [L(N3)Ge:]N3 (2). The latter represents the first isolable diazido Ge(II) complex with a covalently bonded azido ligand and a weakly coordinating azide anion as the counterion. All new compounds 2, 3, and 4 were fully characterized, including using X-ray diffraction analysis.