A single-source molecular precursor [Ba 4 Hf 2 (μ 6 -O) (μ 3 ,η 2 -OR) 8 (μ-OR) 2 (μ-ROH) 4 Cl 4 ] (ROH = CH 3 OCH 2 CH 2 OH) for mixed-metal oxide materials was prepared via elimination of the cyclopentadienyl ring from Cp 2 HfCl 2 as CpH, in the presence of Ba(OR) 2 in an alcohol ROH as a source of protons. The precursor was characterized by elemental analysis, infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy, and single-crystal X-ray structural analysis. This complex undergoes thermal decomposition at 800 °C to a BaCl 2 /BaHfO 3 mixture. After barium dichloride has been leached from the raw powder using deionized water, the resulting particles are of submicrometer size (30À50 nm). Preliminary studies of barium hafnate doped with Eu 3+ sintered at 900 °C showed that a dominant luminescence band belongs to the strong electric dipole transition 5 D 0 f 7 F 2 .

A simple and efficient strategy for the synthesis of nonorganometallic heterometallic clusters from cheap organometallic precursors is reported. This unique synthetic method involves elimination of the cyclopentadienyl ring from Cp(2)MCl(2) (M = Ti, Zr, Hf) as CpH in the presence of M'L(2) or M'L'(2) (M' = Ca, Sr, Mn; CH(3)OCH(2)CH(2)OH = LH or (CH(3))(2)NCH(2)CH(2)OH = L'H) in an alcohol as a source of protons. In the reactions presented, a series of compounds, [Ca(4)Ti(2)(mu(6)-O)(mu(3),eta(2)-L)(8)(eta-L)(2)Cl(4)] (1), [Sr(4)Hf(2)(mu(6)-O)(mu(3),eta(2)-L)(8)(eta-L)(2)(eta-LH)(4)Cl(4)] (2), [Ca(4)Zr(2)(mu(6)-O)(mu-Cl)(4)(mu,eta(2)-L)(8)Cl(2)] (3), [Sr(4)Ti(2)(mu(6)-O)(mu(3),eta(2)-L)(8)(eta-L)(2)(eta-LH)(2)Cl(4)] (4), [Ca(4)Zr(2)Cp(2)(mu(4)-Cl)(mu-Cl)(3)(mu(3),eta(2)-L)(4)(mu,eta(2)-L)(4)Cl(2)] (5), [CaTiCl(2)(mu,eta(2)-L')(3)(eta-L'H)(3)][L'] (6), [Ca(2)Ti(mu,eta(2)-L')(6)Cl(2)] (7), [Mn(4)Ti(4)(mu-Cl)(2)(mu(3),eta(2)-L)(2)(mu,eta(2)-L)(10)Cl(6)] (8), and [Mn(10)Zr(10)(mu(4)-O)(10)(mu(3)-O)(4)(mu(3),eta(2)-L)(2)(mu,eta(2)-L)(16)(mu,eta-L)(4)(eta-L)(2)Cl(8)] (9), were obtained in good yield. All of the complexes were characterized by elemental analysis, IR and NMR spectroscopy, and single-crystal X-ray structural analysis. Complex 8 belongs to a group of magnetic clusters that consists of Mn(4) subunits held together by two mu-Cl bridges. Compounds 6 and 7 underwent thermal decomposition, yielding an alternative source for some heterometallic oxides, which were analyzed by X-ray powder diffraction.

The effect of alkaline-earth-metal alkoxides on the protonolysis of CpM'Cl (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 [MM'(μ-OEt)(μ-OEt)(OEt)(EtOH)] with M = Mg and M' = Ti (1), Zr (2), and Hf (3), [CaTi(μ-O)(μ-O)(μ-OEt)(OEt)(EtOH)Cl] (4), and [MM'(μ-O)(μ-OEt)(OEt)(EtOH)Cl] with M = Ca and M' = Zr (5) and Hf (6) were prepared via elimination of the cyclopentadienyl ring from CpM'Cl as CpH in the presence of M(OEt) and ethanol (EtOH) as a source of protons. Meanwhile, similar reactions involving the initial substitution of Cl ligands by OEt groups in CpM'Cl (M' = Ti, Zr, Hf) resulted in the formation of [MM'(μ-OEt)(μ-OEt)(OEt)(EtOH)] with M = Ca and M' = Ti (7), Zr (8), and Hf (9). The precursors were characterized by elemental analysis, NMR spectroscopy, and single-crystal X-ray structural analysis. Magnesium compounds 1-3 decomposed at 750-850 °C to give MgTiO along with small amounts of MgTiO, MgZrO, or MgHfO binary metal oxides. The thermolysis of calcium compounds 4 and 7-9 led to highly pure CaTiO, CaZrO, or CaHfO perovskite-like oxide particles with diameters of 20-30 nm.

The effect of alkaline earth metal alkoxides on the protonation of zirconocene dichloride was investigated. This approach enabled the design of compounds with preset molecular structures for generating high-purity binary metal oxide perovskites MZrO3 (M=Ba(2+), Sr(2+), Ca(2+)). Single-source molecular precursors [Ba4 Zr2 (μ6 -O)(μ3 ,η(2)-OR)8 (OR)2(η(2) -HOR)2 (HOR)2 Cl4], [Sr4 Zr2 (μ6 -O)(μ3 ,η(2)-OR)8 (OR)2 (HOR)4 Cl4], [Ca4 Zr2 (μ6-O)(μ3 ,η(2)-OR)8 (OR)2 Cl4], and [Ca6 Zr2 (μ2 ,η(2)-OR)12 (μ-Cl)2 (η(2) -HOR)4 Cl6 ]⋅8 CH2 Cl2 were prepared via elimination of the cyclopentadienyl ring from Cp2 ZrCl2 as CpH in the presence of M(OR)2 and alcohol ROH (ROH=CH3OCH2 CH2OH) as a source of protons. The resulting complexes were characterized by elemental analysis, IR and NMR spectroscopy, and single-crystal X-ray diffraction. The compounds were then thermally decomposed to MCl2 /MZrO3 mixtures. Leaching of MCl2 from the raw powder with deionized water produced highly pure perovskite-like oxide particles of 40-80 nm in size. Luminescence studies on Eu(3+)-doped MZrO3 revealed that the perovskites are attractive host lattices for potential applications in display technology.

A simple new route to access heterometallic alkoxo precursors for a wide range of materials is reported. This unique synthetic method comprises elimination of the cyclopentadienyl ring from Cp2MCl2 (M = Ti, Zr) as CpH in the presence of M'(OR)2 (M' = Ca, Mn; OR = OCH2CH2OCH3 or OEt) in an alcohol as a source of protons. In one-pot reactions, we have prepared four different compounds with Ti2Ca4(mu6-O), Cp2Zr2Ca4(mu4-Cl), Zr10Mn10(mu3-O) 14, and Cp3Ti2(mu-OEt)2 motifs. The compounds were characterized by single-crystal X-ray structural analysis and NMR spectroscopy.