Reduction of Digermenes with Alkali Metals:  Salts of Formula M₂[{Ge(H)Ar‘}₂] (M = Li, Na, or K, Ar‘ = Terphenyl) with Three Different Structures

The reduction of the digermene Ar‘(H)GeGe(H)Ar‘ (Ar‘ = C₆H₃-2,6(C₆H₃-2,6-Prⁱ₂)₂) with Li, Na, or K afforded [Li(THF)₃Et₂O][LiAr‘(H)GeGe(H)Ar‘] (1), Na₂Ar‘Ge(μ-H)₂GeAr‘ (2), or K₂{Ar‘(H)GeGe(H)Ar‘} (3), which have three different structures. 1 features a planar C(ipso)H)GeGe(H)C(ipso) dianion core with an associated Li⁺ cation. In contrast, 2 features a unique bridged hydride structure in which two Na⁺ ions also bridge the germaniums. In 3, the C(ipso)(H)GeGe(H)C(ipso) array has a nonplanar trans bent core with associated K⁺ ions. There is single Ge−Ge bonding in 1 and 3, but the Ge−Ge bonding in 2 may involve biradical character.