Insertion\nBehavior of Dialkylgermylene Ge(Flu<sup>TMS</sup>)<sub>2</sub> in\nDifferent E–X σ Bonds (E =\nAu, Si, Ge, Sn) and Its Relevance for Germanium Cluster Formation

We present the insertion behavior of the alkyl-substituted\ngermylene\nGe­(Flu<sup>TMS</sup>)<sub>2</sub> in different E–X σ\nbonds (E = Au, Si, Ge, Sn), first with the isolation of the germylgold\ncomplex (Flu<sup>TMS</sup>)<sub>2</sub>Ge­(Cl)­AuPPh<sub>3</sub>. Afterward,\nthe oxidative addition of GeCl<sub>4</sub> to Ge­(Flu<sup>TMS</sup>)<sub>2</sub> gives the digermane (Flu<sup>TMS</sup>)<sub>2</sub>Ge­(Cl)­GeCl<sub>3</sub>, followed by a reductive elimination of GeCl<sub>2</sub> and the formation of the oxidation product (Flu<sup>TMS</sup>)<sub>2</sub>GeCl<sub>2</sub>. A comparable behavior is observed,\nwith the homologues ECl<sub>4</sub> (E = Si, Sn) stopping at different\nsteps of the reaction. The formation of the germylgermylene (Flu<sup>TMS</sup>)<sub>2</sub>Ge­(Cl)­GeCl starting from Ge­(Flu<sup>TMS</sup>)<sub>2</sub> and GeCl<sub>2</sub>·dioxane is also spectroscopically\nobservable, followed by ligand rearrangements to the tetramer [Flu<sup>TMS</sup>GeCl]<sub>4</sub>. Adding a phosphine as the Lewis base\nhas a direct influence on the stability and structure of (Flu<sup>TMS</sup>)<sub>2</sub>Ge­(Cl)­GeCl, leading to the formation of Flu<sup>TMS</sup>GeCl·PEt<sub>3</sub> as a stable product. Subsequent\ninvestigations of Ge­(Flu<sup>TMS</sup>)<sub>2</sub> with a metastable\nGe­(I)Br solution show that at a ratio of 6:1 GeBr/Ge­(Flu<sup>TMS</sup>)<sub>2</sub> the alkyl-substituted germylene no longer acts as a\nredox-active agent but as a cluster building block. This link and\nthe involvement of a germylene in insertion reactions give an indication\nof how the construction or expansion of Ge cluster species can operate.