Functionalization of [Ge9] with Small Silanes:[Ge9(SiR3)3]-(R =iBu,iPr, Et) and the Structures of (CuNHCDipp)[Ge9{Si(iBu)3}3], (K-18c6)Au[Ge9{Si(iBu)3}3]2, and (K-18c6)2[Ge9{Si(iBu)3}2]

Novel silylation reactions at [Ge9] Zintl clusters starting from the chlorosilanes SiR3Cl (R = iBu, iPr, Et) and the Zintl phase K4Ge9 are reported. The formation of the tris-silylated anions [Ge9(SiR3)3]– [R = iBu (1a), iPr (1b), Et (1c)] by heterogeneous reactions in acetonitrile was monitored by ESI-MS measurements. For R = iBu 1H, 13C and 29Si NMR experiments confirmed the exclusive formation of 1a. Subsequent reactions of 1a with CuNHCDippCl and Au(PPh3)Cl result in formation of the neutral metal complex (CuNHCDipp)[Ge9{Si(iBu)3}3]·0.5 tol (2·0.5 tol) and the metal bridged dimeric unit {Au[Ge9{Si(iBu)3}3]2}– (3a), isolated as a (K-18c6)+ salt in (K-18c6)Au[Ge9{Si(iBu)3}3]2·tol (3·tol), respectively. Finally, from a toluene/hexane solution of 1a in presence of 18-crown-6, crystals of the compound (K-18c6)2[Ge9{Si(iBu)3}2]·tol (4·tol), containing the bis-silylated cluster anion [Ge9(Si(iBu)3)2]2– (4a), were obtained. The compounds 2·0.5 tol, 3·tol and 4·tol were characterized by single-crystal structure determination.