Diene and arene compounds of zirconium and hafnium

Abstract

The diene compounds [Hf(η⁴-CH₂CMeCMeCH₂)(PMe₃)₂Cl₂]1, [M(η⁴-C₆H₈)(PMe₃)₂Cl₂](M = Zr 2 or Hf 3) and the divalent [Zr(η⁶-C₆H₅Me)(PMe₃)₂Cl₂]5 have been prepared. The structure of compound 1 has been determined by low-temperature neutron diffraction (15 K) and the σ², π nature of the bonding mode of the 2,3-dimethylbutadiene ligand demonstrated from the methylene hydrogen positions. Treatment of 1 with lithium indenide gave [Hf(η⁵-C₉H₇)₂(η⁴-CH₂CMeCMeCH₂)]4. The crystal structure of 5 has been determined by X-ray diffraction.