Steric Effect of a Phosphane Ligand on the Equilibrium of Ge–Ge Bond Formation at a Platinum Center

Abstract

AbstractReactions of zero‐valent platinum complexes having a diphosphane ligand with arylgermanes ArGeH3 [Ar = 2,4,6‐trimethylphenyl (Mes); 2,4,6‐triethylphenyl (TEP)] in a 1:2 molar ratio yield several bis(germyl)platinum complexes. The complex containing a five‐membered chelate ligand (dppe) is thermally stable even at 80 °C. Analogues bearing a six‐membered chelate ligand (dppp) were converted into the digermylplatinum complex through a 1,2‐germyl migration, and an equilibrium between the bis(germyl) and digermyl complexes was observed. In a comparison of the crystal structures, the bite angle of dppp is significantly larger than that of dppe, causing a reduction of the phosphane–germyl ligand distance. The 1,2‐germyl migration of the platinum center to the other germanium atom contributes to the decrease in steric repulsion between the phosphane and germyl ligands.