4,4′-Biphenolate complexes of titanium and zirconium

Denise L. Barnes, Nancy W. Eilerts, Joseph A. Heppert

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


4,4′-Biphenolate ligands (R4BIPOH2) bearing methyl or tert-butyl substituents in the 3,3′,5,5′-positions participate in alcoholysis reactions with metal precursors, including TiCl4, Ti(OiPr)4 and Cp2MCl2. The tetra-tert-butyl derivative shows evidence of an intermediate monotitanium species (Bu4BIPOH)Ti(OiPr)3 during titrations of the ligand with Ti(OiPr)4, while (Bu4BIPO)(TiOiPr)3)2 exists as a simple monomeric molecule in solution. (Me4BIPO)(Ti(OiPr)3)2 shows evidence of aggregation into oligomeric species in solution, although its insolubility hampered the complete characterization of these species. A reaction between the d1 complex TiCl3(THF)3 and 3,3′,5,5′-tBu4-4,4′-biphenoquinone produced (Bu4BIPO)[TiCl3(THF)]2, while dirct reactions between TiCl4 and Bu4BIPOH2 in toluene resulted in the isolation of the dealkylated product, (Bu2BIPO)[TiCl3(Et2O)]2 (where the tBu groups occur in the 3,3′-positions), after treatment with ether. Refluxing Me4BIPOH2 and Cp2MCl2 (M = Ti or Zr) in toluene produced bismetallocene chloride complexes.

Original languageEnglish
Pages (from-to)743-748
Number of pages6
Issue number5
StatePublished - 1994


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