Synthesis, characterization and catalytic behaviour of ansa-zirconocene complexes containing tetraphenylcyclopentadienyl rings: X-ray crystal structures of [Zr{Me2Si(η5-C5Ph4)(η5-C5H3R)}Cl2] (R = H, But)

The synthesis and structural characterization of the ansa-zirconocene complexes, [Zr{Me2Si(η5-C5Ph4)(η5-C5H3R)}Cl2] (R = H and But), are reported. They have been tested as catalysts in the polymerization and found to be inactive. In order to explain this, DFT calculations based on the transition states present in the polymerization process have been carried out.