[Ph₂Bi−(Ge₉)−BiPh₂]^2-: A Deltahedral Zintl Ion Functionalized by Exo-Bonded Ligands

The title anion was synthesized by a reaction of nido-Ge94-, made from K4Ge9 dissolved in ethylenediamine and 2,2,2-crypt(4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane), with BiPh3. It was structurally characterized in (K-2,2,2-crypt)2[Ge9(BiPh2)2]·en which was crystallized from the solution. The anion is a monocapped square antiprism of Ge9 with two diphenylbismuth ligands exo-bonded to opposite vertexes of the open face of the cluster. This is the first example where covalently exo-bonded ligands are attached to a deltahedral cluster that can exist without them as well.