Reaction of [η5-C5H5)2ZrH(μ-H)]2 with diphenylacetylene: mechanistic and theoretical considerations

The polymeric (Cp2ZrH2)x molecule is shown by 1H NMR studies to adopt a dimeric structure with bridging and terminal hydride ligands in both benzene-d6 and toluene-d8 solution. The reaction of the zirconium dihydride with diphenylacetylene has been re-investigated and produces a zirconacyclopentadiene complex 7, contrary to literature suggestions of a dimetallic zirconabenzene structure. A qualitative molecular orbital analysis of the [Cp2ZrH(μ-H)]2 dimer lends support to a suggested mechanism involving reaction with diphenylacetylene via a dimeric species.