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.