Heterobimetallic molecular cages for the deposition of Cu/Ti and Cu/Zn mixed-metal oxides.

Heterobimetallic molecular precursors [Ti4(dmae)6(mu-OH)(mu-O)6Cu6(OAc)9.H2O] (1) and [Zn7(OAc)10(mu-OH)6Cu5(dmae)4Cl4] (2) for the deposition of metal oxide thin films of Cu6Ti4O12 (Cu3TiO4, TiO2) and Cu5Zn7O12 (ZnO, CuO) were prepared by the interaction of Ti(dmae)4 with Cu(OAc)2.2H2O for 1 and tetrameric (N,N-dimethylamino)ethanolatocopper(II) chloride, [(dmae)CuCl]4 [where dmae = (N,N-dimethylamino)ethanolate] with Zn(OAc)2.2H2O (where OAc = acetate) for 2 in dry toluene. Both complexes were characterized by melting point, elemental analysis, Fourier transform IR, fast atom bombardment mass spectrometry, thermal analysis (TGA), and single-crystal X-ray diffraction. TGA and XRD prove that complexes 1 and 2 undergo facile thermal decomposition at 300 and 460 degrees C to form thin films of Cu/Ti and Cu/Zn mixed-metal oxides, respectively. Scanning electron microscopy and XRD of the thin films suggest the formation of impurity-free crystallite mixtures of Cu3TiO4 and TiO2, with average crystallite sizes of 22.2 nm from complex 1 and of ZnO and CuO with average crystallite sizes of 26.1 nm from complex 2.