Synthesis and Characterization of Three Multi-Shell Metalloid Gold Clusters Au32(R3P)12Cl8

Three multi-shell metalloid gold clusters of the composition Au-32(R3P)(12)Cl-8 (R=Et, Pr-n, Bu-n) were synthesized in a straightforward fashion by reducing R3PAuCl with NaBH4 in ethanol. The Au-32 core comprises two shells, with the inner one constituting a tilted icosahedron and the outer one showing a distorted dodecahedral arrangement. The outer shell is completed by eight chloride atoms and twelve R3P groups. The inner icosahedron shows bond lengths typical for elemental gold while the distances of the gold atoms in the dodecahedral arrangement are in the region of aurophilic interactions. Quantum-chemical calculations illustrate that the Jahn-Teller effect observed within the cluster core can be attributed to the electronic shell filling. The easily reproducible synthesis, good solubility, and high yields of these clusters render them perfect starting points for further research.