Synthesis of Aluminosilicates Containing a Ba(Sr)–O–Al–O–Si Arrangement of Natural Feldspar Mineral

We report a facile route to multicomponent complexes of [M­{(μ-ddbfo)₂Al­(OSiR₃)₂}₂] (M = Ba, Sr; ddbfoH = 2,3-dihydro-2,2-dimethylbenzofuran-7-ol; R = Ph, O^tBu) as new efficient single-source routes to barium and strontium celsian feldspar Ba­(Sr)­Al₂Si₂O₈. The resulting complexes were characterized by elemental analysis, IR and NMR spectroscopy, and single-crystal X-ray diffraction. These compounds calcined at 1100 °C to give porous material Ba­(Sr)­Al₂Si₂O₈·2SiO₂ as an amorphous silica matrix containing spherical oxide nanocrystals of celsian feldspar of ca. 5 nm diameter, as evidenced by transmission and scanning electron microscopies

Synthesis of Aluminosilicates Containing a Ba(Sr)–O–Al–O–Si Arrangement of Natural Feldspar Mineral

We report a facile route to multicomponent complexes of [M­{(μ-ddbfo)₂Al­(OSiR₃)₂}₂] (M = Ba, Sr; ddbfoH = 2,3-dihydro-2,2-dimethylbenzofuran-7-ol; R = Ph, O^tBu) as new efficient single-source routes to barium and strontium celsian feldspar Ba­(Sr)­Al₂Si₂O₈. The resulting complexes were characterized by elemental analysis, IR and NMR spectroscopy, and single-crystal X-ray diffraction. These compounds calcined at 1100 °C to give porous material Ba­(Sr)­Al₂Si₂O₈·2SiO₂ as an amorphous silica matrix containing spherical oxide nanocrystals of celsian feldspar of ca. 5 nm diameter, as evidenced by transmission and scanning electron microscopies

Molecular Routes to Group IV Magnesium and Calcium Nanocrystalline Ceramics

The effect of alkaline-earth-metal alkoxides on the protonolysis of Cp₂M′Cl₂ (M′ = Ti, Zr, Hf; Cp = cyclopentadiene) was investigated. This approach enabled the design of compounds with well-defined molecular structures to generate high-purity binary metal oxides. Single-source molecular precursors with structures of [M₂M′₂(μ₃-OEt)₂(μ-OEt)₄(OEt)₆(EtOH)₄] with M = Mg and M′ = Ti (<b>1</b>), Zr (<b>2</b>), and Hf (<b>3</b>), [Ca₆Ti₄(μ₆-O)₂(μ₄-O)₂(μ₃-OEt)₁₂(OEt)₁₂(EtOH)₆Cl₄] (<b>4</b>), and [M₂M′₂(μ₄-O)­(μ-OEt)₅(OEt)₄(EtOH)₄Cl]_<i>n</i> with M = Ca and M′ = Zr (<b>5</b>) and Hf (<b>6</b>) were prepared via elimination of the cyclopentadienyl ring from Cp₂M′Cl₂ as CpH in the presence of M­(OEt)₂ and ethanol (EtOH) as a source of protons. Meanwhile, similar reactions involving the initial substitution of Cl ligands by OEt groups in Cp₂M′Cl₂ (M′ = Ti, Zr, Hf) resulted in the formation of [M₂M′₂(μ₃-OEt)₂(μ-OEt)₄(OEt)₆(EtOH)₄] with M = Ca and M′ = Ti (<b>7</b>), Zr (<b>8</b>), and Hf (<b>9</b>). The precursors were characterized by elemental analysis, NMR spectroscopy, and single-crystal X-ray structural analysis. Magnesium compounds <b>1</b>–<b>3</b> decomposed at 750–850 °C to give MgTiO₃ along with small amounts of Mg₂TiO₄, Mg₂Zr₅O₁₂, or Mg₂Hf₅O₁₂ binary metal oxides. The thermolysis of calcium compounds <b>4</b> and <b>7</b>–<b>9</b> led to highly pure CaTiO₃, CaZrO₃, or CaHfO₃ perovskite-like oxide particles with diameters of 20–30 nm

Unexpected Reactions between Ziegler–Natta Catalyst Components and Structural Characterization of Resulting Intermediates

In this work, we investigated precursors and procatalysts with well-defined crystal structures and morphologies in Ziegler–Natta systems to improve our understanding of the nature of the active metal sites. Molecular cluster precursors such as [Mg₄Ti₃(μ₆-O)­(μ₃-OH)₃(μ-OEt)₉(OEt)₃(EtOH)₃Cl₃], [Mg₄Ti₃(μ₆-O)­(μ₃-OH)­(μ₃-OEt)₂(μ-OEt)₉(OEt)₃(EtOH)₃Cl₃], and [Mg₆Ti₄(μ₆-O)₂(μ₃-OH)₄(μ-OEt)₁₄(OEt)₄(EtOH)₂Cl₂] were prepared via simple elimination of the cyclopentadienyl ring from Cp₂TiCl₂ as CpH in the presence of magnesium metal and ethanol. Titanocene dichloride acts as both a source of titanium and a magnesium-chlorinating agent. The resulting novel complexes were characterized using single-crystal X-ray diffraction. In these compounds, Ti­(OEt)₄ molecules are grafted onto Mg₄ and Mg₆ ethoxide cubane-like surfaces; this strongly affects the procatalyst morphology, which is transferred to the polymer. Mg₄(OR)₈ units act as carriers for the AlR₃ co-catalyst, resulting in return of alkyl functions to the Ti center

Transformation of Barium–Titanium Chloro–Alkoxide Compound to BaTiO₃ Nanoparticles by BaCl₂ Elimination

In this Article, we present how the molecular precursor of binary oxide material having an excess of alkali earth metal can be transformed to the highly phase pure BaTiO₃ perovskite. Here, we synthesized and compared two barium–titanium complexes with and without chloride ligands to determine the influences of different ligands on the phase purity of binary oxide nanoparticles. We prepared two barium–titanium complexes, i.e., [Ba₄Ti₂(μ₆-O)­(OCH₂CH₂OCH₃)₁₀­(HOCH₂CH₂OCH₃)₂­(HOOCCPh₃)₄] (<b>1</b>) and [Ba₄Ti₂(μ₆-O)­(μ₃,η₂-OCH₂CH₂OCH₃)₈­(μ-OCH₂CH₂OCH₃)₂­(μ-HOCH₂CH₂OCH₃)₄Cl₄] (<b>2</b>). The barium–titanium precursors were characterized using elemental analysis, infrared and nuclear magnetic resonance spectroscopies, and single-crystal X-ray structural analysis, and their thermal decomposition products were compared. The complex <b>1</b> decomposed at 800 °C to give a mixture of BaTiO₃ and Ba₂TiO₄, whereas <b>2</b> gave a BaCl₂/BaTiO₃ mixture. Particles of submicrometer size (30–50 nm) were obtained after leaching of BaCl₂ from the raw powder using deionized water. Preliminary studies of barium titanate doped with Eu³⁺ sintered at 900 °C showed that the dominant luminescence band arose from the strong electric dipole transition, ⁵D₀–⁷F₂

Transformation of Barium–Titanium Chloro–Alkoxide Compound to BaTiO₃ Nanoparticles by BaCl₂ Elimination

In this Article, we present how the molecular precursor of binary oxide material having an excess of alkali earth metal can be transformed to the highly phase pure BaTiO₃ perovskite. Here, we synthesized and compared two barium–titanium complexes with and without chloride ligands to determine the influences of different ligands on the phase purity of binary oxide nanoparticles. We prepared two barium–titanium complexes, i.e., [Ba₄Ti₂(μ₆-O)­(OCH₂CH₂OCH₃)₁₀­(HOCH₂CH₂OCH₃)₂­(HOOCCPh₃)₄] (<b>1</b>) and [Ba₄Ti₂(μ₆-O)­(μ₃,η₂-OCH₂CH₂OCH₃)₈­(μ-OCH₂CH₂OCH₃)₂­(μ-HOCH₂CH₂OCH₃)₄Cl₄] (<b>2</b>). The barium–titanium precursors were characterized using elemental analysis, infrared and nuclear magnetic resonance spectroscopies, and single-crystal X-ray structural analysis, and their thermal decomposition products were compared. The complex <b>1</b> decomposed at 800 °C to give a mixture of BaTiO₃ and Ba₂TiO₄, whereas <b>2</b> gave a BaCl₂/BaTiO₃ mixture. Particles of submicrometer size (30–50 nm) were obtained after leaching of BaCl₂ from the raw powder using deionized water. Preliminary studies of barium titanate doped with Eu³⁺ sintered at 900 °C showed that the dominant luminescence band arose from the strong electric dipole transition, ⁵D₀–⁷F₂

Transformation of Barium–Titanium Chloro–Alkoxide Compound to BaTiO₃ Nanoparticles by BaCl₂ Elimination

In this Article, we present how the molecular precursor of binary oxide material having an excess of alkali earth metal can be transformed to the highly phase pure BaTiO₃ perovskite. Here, we synthesized and compared two barium–titanium complexes with and without chloride ligands to determine the influences of different ligands on the phase purity of binary oxide nanoparticles. We prepared two barium–titanium complexes, i.e., [Ba₄Ti₂(μ₆-O)­(OCH₂CH₂OCH₃)₁₀­(HOCH₂CH₂OCH₃)₂­(HOOCCPh₃)₄] (<b>1</b>) and [Ba₄Ti₂(μ₆-O)­(μ₃,η₂-OCH₂CH₂OCH₃)₈­(μ-OCH₂CH₂OCH₃)₂­(μ-HOCH₂CH₂OCH₃)₄Cl₄] (<b>2</b>). The barium–titanium precursors were characterized using elemental analysis, infrared and nuclear magnetic resonance spectroscopies, and single-crystal X-ray structural analysis, and their thermal decomposition products were compared. The complex <b>1</b> decomposed at 800 °C to give a mixture of BaTiO₃ and Ba₂TiO₄, whereas <b>2</b> gave a BaCl₂/BaTiO₃ mixture. Particles of submicrometer size (30–50 nm) were obtained after leaching of BaCl₂ from the raw powder using deionized water. Preliminary studies of barium titanate doped with Eu³⁺ sintered at 900 °C showed that the dominant luminescence band arose from the strong electric dipole transition, ⁵D₀–⁷F₂