Mono-, Di-, and Trimetallic Methacrylate-substituted Metal Oxide Clusters Derived from Hafnium Butoxide

 The methacrylate-substituted clusters Hf4O2(OMc)12, Hf6O4(OH)4(OMc)12(BuOH), Ti4Hf4O6(OBu)4(OMc)16, and Ti2Zr5HfO6(OMc)20 (OMc=methacrylate) were prepared by reacting Hf(OBu)4, or Hf(OBu)4/Ti(OBu)4 and Hf(OBu)4/Zr(OBu)4/Ti(OBu)4 mixtures, respectively, with methacrylic acid. All clusters were characterized by X-ray structure analyses and are basically isostructural, although not in each case isomorphous, with the corresponding oxozirconium clusters. Low-temperature NMR studies revealed that the methacrylate ligands of Hf4O2(OMc)12 are highly dynamic even at −80°C.