Tetrapalladium Complex with Bridging Germylene Ligands. Structural Change of the Planar Pd₄Ge₃ Core

A complex with a planar hexagonal Pd4Ge3 core, [Pd{Pd(dmpe)}3(μ3-GePh2)3], was synthesized and characterized by X-ray and NMR measurements as well as by DFT calculations. 4-tert-Butylbenzenethiol converted the Pd4 complex into a hexapalladium complex, [{Pd3(μ-GePh2)2(μ-H)(μ3-GePh2(SC6H4tBu-4))}2(μ-dmpe)], composed of two Pd3Ge3 units bridged by a dmpe ligand. The addition of CuI or AgI to the Pd4 complex yielded [Pd(μ-MI){Pd(dmpe)}3(μ3-GePh2)3 ] (M = Cu, Ag), in which Cu or Ag bridges a Pd–Pd bond of the Pd4Ge3 core. The CuI adducts in solution undergo a pivot motion of the CuI on the surface of the Pd4Ge3 plane on the NMR time scale.