In view of their relevance for many catalytic processes, the field of transition-metal complexes containing metal–silicon bonds has received considerable attention over the last decades. M⁰ complexes of Group 10 metals with Si-containing ligands, in particular homoleptic ones, are only known with silylene ligands (SiR₂). Therefore, Frank Breher and his group, Karlsruhe Institute of Technology (KIT), Germany, have become interested in investigating how analogous d¹⁰ silyl (SiR₃) complexes of palladium(0) and platinum(0) might be accessible.

By using a multifunctional silyl ligand based on the tris(3,5-dimethylpyrazolyl)silyl scaffold [Si(3,5-Me₂pz)₃]^–, they succeeded in obtaining the homoleptic tetrakis(silyl) complexes of Pd⁰ and Pt⁰, which were characterized by various methods, including multinuclear NMR spectroscopic techniques, cyclic voltammetry in combination with DFT calculations, X-ray crystallography, and EPR spectroscopy. The complexes form very unusual metal-centered heterocubane structures in the solid state and in solution. The rather rigid heterocubane ligand shells were found to facilitate the stepwise, quasi-reversible oxidation to their d⁹ M^I and d⁸ M^II analogues.

• Homoleptic Tetrakis(silyl) Complexes of Pd⁰ and Pt⁰ Featuring Metal-Centred Heterocubane Structures: Evidence for the Existence of the Corresponding Mononuclear Pd^I and Pt^I Complexes,
  F. Armbruster, T. Augenstein, P. Oña-Burgos, F. Breher,
  Chem. Eur. J. 2013.
  DOI: 10.1002/chem.201303299