Convenient Route to Heterometallic Group 4-Zinc Precursors for Binary Oxide Nanomaterials.

In this study, simple and efficient synthetic routes to a family of uncommon group 4-zinc heterometallic alkoxides were developed. Single-source molecular precursors with the structures [CpTiZn(μ,η-OR)(THF)Cl] (), [ZrZn(μ-O)(μ,η-OR)(μ-OH)(μ,η-OR)(μ,η-OR)Cl] (), and [HfZn(μ-O)(μ,η-OR)(μ-OH)(μ,η-OR)(μ,η-OR)Cl] () were prepared via reduction of CpTiCl with metallic zinc or protonolysis of the metal-cyclopentadienyl bond in CpM'Cl (M' = Zr or Hf) in the presence of 2-methoxyethanol (ROH) and Zn(OR). This synthetic route enables the creation of compounds with well-defined molecular structures and therefore provides precursors suitable for obtaining group 4-zinc oxides. Precursors - were characterized by elemental analysis, nuclear magnetic resonance and infrared spectroscopies, and single-crystal X-ray diffraction. Compound decomposed at 800-900 °C to give a mixture of binary metal oxides (i.e., ZnTiO, ZnTiO, or ZnTiO) and common polymorphs of TiO and ZnO. After calcination at 1000 °C, only TiO and the high-temperature-stable phase ZnTiO were observed. Thermolysis of compounds and gave mixtures of ZnO and ZrO or HfO, respectively. The obtained ZnO-ZrO and ZnO-HfO mixed oxide materials have constant phase compositions across a broad temperature range and therefore are attractive host lattices for Eu for applications as yellow/red double-light-emitting phosphors. It was established that Eu ions were successfully introduced into the ZnO and ZrO/HfO lattices. It was revealed that Eu ions prefer to occupy low-symmetry sites in ZrO/HfO rather than in ZnO.