Deltahedral Germanium Clusters: Insertion of Transition-Metal Atoms and Addition of Organometallic Fragments

Reactions of nine-atom deltahedral clusters of germanium with Ni(COD)2 and/or Ni(PPh3)2(CO)2
in ethylenediamine yielded the Ni-centered heteroatomic 10-atom clusters [Ni@(Ge9Ni−CO)]2- and
[Ni@(Ge9Ni−en)]3-, as well as the empty 10-atom heteroatomic cluster [Ge9Ni−CO]3-. A ligand exchange
reaction between [Ni@(Ge9Ni−CO)]2- and potassium phenylacetylide produced the organically functionalized
species [Ni@(Ge9Ni−CCPh)]3-. The empty cluster [Ge9Ni−CO]3- is a bicapped square antiprism where
one of the capping vertexes is the nickel atom. The other three clusters are tricapped trigonal prisms where
an additional 10th vertex of monoligated nickel caps a triangular base of the trigonal prism. As a result of
this, that base opens up, and the distances within it become nonbonding. This ensures that all atoms of
the cluster are equidistant from the central nickel atom, i.e., the cluster is very close to spherical. All species
were structurally characterized in crystalline compounds with [K-(2,2,2-crypt)]+ countercations. They were
also characterized in solution by mass spectrometry, IR, and 13C NMR.