Synthesis and Reactivity of a Zwitterionic Palladium Allyl Complex Supported by a Perchlorinated Carboranyl Phosphine

A zwitterionic palladium complex
of a phosphine bearing a perchlorinated carba-closo-dodecaborate anion as a ligand substituent is reported. A single-crystal
X-ray diffraction study reveals that, in the solid state, one of the
chlorides of the carborane cage occupies a coordination site of the
square-planar complex. However, in solution, the P–carborane
bond of the ligand is rapidly rotating at temperatures as low as −90
°C, which demonstrates the carborane substituent’s weak
coordinative ability even though this anion is covalently linked to
the phosphine ligand. The complex is thermally stable and catalyzes
the vinyl addition polymerization of norbornene.