Square-Planar Anionic Pt 0 Complexes.

A T-shaped Pt complex with a diphosphine-borane (DPB) ligand was prepared. The Pt→B interaction enhances the electrophilicity of the metal and triggers the addition of Lewis bases to give the corresponding tetracoordinate complexes. For the first time, anionic Pt complexes are isolated and structurally authenticated. X-ray diffraction analyses show the anionic complexes [(DPB)PtX] (X=CN, Cl, Br, I) to be square-planar. The d configuration and Pt oxidation state of the metal were unambiguously established by X-ray photoelectron spectroscopy and DFT calculations. The coordination of Lewis acids as Z-type ligands is a powerful mean to stabilize elusive electron-rich metal complexes and achieve uncommon geometry.