[(Me3 Si)Si]3 EtGe9 Pd(PPh3 ), a Pentafunctionalized Deltahedral Zintl Cluster: Synthesis, Structure, and Solution Dynamics

The title compound, which has a ten-atom deltahedral cluster core of Ge9 Pd, was synthesized through insertion of Pd(PPh3 ) into the tetrasubstituted nona-germanium cluster [(Me3 Si)Si]3 EtGe9 through a reaction of the latter with Pd(PPh3 )4 . This first reaction of neutral tetrasubstituted nine-atom clusters shows that they retain reactivity despite their neutral charge. The Ge9 Pd core is the first that incorporates a 5-connected transition metal other than from Group VI, a noble metal in this case. Single-crystal X-ray diffraction shows that the ten-atom core is a closo-cluster with the expected shape of a bicapped square antiprism. (1) H and (13) C NMR spectroscopy show that, in contrast to the parent tetra-substituted [(Me3 Si)Si]3 EtGe9 , the new compound does not exhibit dynamics. Relativistic DFT calculations are used to explain the differences.