Low-valent Ge(2) and Ge(4) species trapped by N-heterocyclic gallylene.

Much π and no σ: quantum chemical calculations showed that the Ge atoms of the Ga(2)Ge(2) core in Ge(2)[Ga(DPP)](2) are not bonded by σ interactions, but rather by a transannular π interaction. The compound is formed by reduction of (PCy(3))⋅GeCl(2) with Ga(DDP)/KC(8) which also yielded a further product Ge(4)[Ga(DPP)](2) with a Ge(4) tetrahedron (DDP=HC(CMeNC(6)H(3)-2,6-iPr(2))(2)).