On the Reactivity of Silylated Ge9 Clusters: Synthesis and Characterization of [ZnCp*(Ge9 {Si(SiMe3 )3 }3 )], [CuPiPr3 (Ge9 {Si(SiMe3 )3 }3 )], and [(CuPiPr3 )4 {Ge9 (SiPh3 )2 }2 ].

We report on the synthesis of new derivatives of silylated clusters of the type [Ge9 (SiR3 )3 ]- (R = SiMe3 , Me = CH3 ; R = Ph, Ph = C6 H5 ) as well as on their reactivity towards copper and zinc compounds. The silylated cluster compounds were synthesized by heterogeneous reactions starting from the Zintl phase K4 Ge9 . Reaction of K[Ge9 {Si(SiMe3 )3 }3 ] with ZnCl2 leads to the already known dimeric compound [Zn(Ge9 {Si(SiMe3 )3 }3 )2 ] (1), whereas upon the reaction with [ZnCp*2 ] the coordination of [ZnCp*]+ to the cluster takes place (Cp*=1,2,3,4,5-pentamethylcyclopentadienyl) under the formation of [ZnCp*(Ge9 {Si(SiMe3 )3 }3 )] (2). A similar reaction leads to [CuPiPr3 (Ge9 {Si(SiMe3 )3 }3 )] (3) from [CuPiPr3 Cl] (iPr=isopropyl). Further we investigated the novel silylated cluster units [Ge9 (SiPh3 )3 ]- (4) and [Ge9 (SiPh3 )2 ]- (5), which could be identified by mass spectroscopy. Bis- and tris-silylated species can be synthesized by the respective stoichiometric reactions, and the products were characterized by ESI-MS and NMR experiments. These clusters show rather different reactivity. The reaction of the tris-silylated anion 4 with [CuPiPr3 Cl] leads to [(CuPiPr3 )3 Ge9 (SiPh3 )2 ]+ as shown from NMR experiments and to [(CuPiPr3 )4 {Ge9 (SiPh3 )2 }2 ] (6), which was characterized by single-crystal X-ray diffraction. Compound 6 shows a new type of coordination of the Cu atoms to the silylated Zintl clusters.