Capping <i>nido</i>-Nonagermanide Clusters with <i>M</i>-PPh₃ and Dynamics in Solution: Synthesis and Structure of <i>closo</i>-[(Me₃Si)₃Si]₃Et[Ge₉<i>M</i>](PPh₃) (<i>M</i> = Ni, Pt)

Abstract

In this work, cluster expansion of nine-atomic germanium clusters with nickel and platinum atoms is reported. The compounds [(Me3Si)3Si]3Et[Ge9Ni](PPh3) and [(Me3Si)3Si]3Et[Ge9Pt](PPh3) are characterized by NMR spectroscopy, elemental analysis, and single crystal X-ray structure analysis. The latter represents the first intermetalloid Ge-Pt cluster with a platinum atom as part of a deltahedron. So far, only one compound of this type has been reported for the homologous Pd. Hence, with these new compounds, metal-coordinated deltahedral Ge9 clusters are now known for the whole triad of group 10 elements. The cluster compounds are accessible by treating [(Me3Si)3Si]3EtGe9 with η2-ethylene-bis-(triphenylphosphine)-nickel(0) and η2-ethylene-bis-(triphenylphosphine)-platinum(0), respectively, in toluene. The crystal structure determination reveals ten-vertex-closo-[Ge9M]-cluster cores (M = Ni, Pt) bearing five exo-bonded ligands. Unlike the nine-vertex-cluster [(Me3Si)3Si]3EtGe9, the penta-functionalized platinum containing cluster compound [(Me3Si)3Si]3Et[Ge9Pt](PPh3) does not show fluctuating behavior in solution over a wide temperature range on the NMR time scale, whereas the [(Me3Si)3Si]3Et[Ge9Ni](PPh3) shows highly dynamic processes in solution at ambient temperature.