Große Übergangsmetallcluster, IV Ru55-, Rh55- und Pt55-Cluster / Large Transition Metal Clusters, IV Ru55-, Rh55- and Pt55-Clusters

The novel cluster compounds Ru55[P (tert -Bu)3]12Cl20, Rh55(PPh3)12Cl6 and Pt55[As(tert -Bu)3]12Cl20 have been prepared by the reaction of (RuCl3/P (tert-Bu)3), (Ph3P)3RhCl and trans-[As(tert -Bu)3]2PtCl2, respectively, with B2H6 in THF or benzene. Diborane reduces the metal salts and serves to capture excess of phosphine or arsine ligands. Molecular weight determinations prove the cluster size. High resolution transmission electron microscopic investigations on the Pt55 cluster show the expected full-shell cuboctahedron with 55 closest-packed platinum atoms. 31P NMR spectra prove the ligands to be very mobile.