Heterometallic Group 4–Lanthanide Oxo-alkoxide Precursors for Synthesis of Binary Oxide Nanomaterials

Abstract

In this study, an efficient procedure for the synthesis of uncommon group 4–lanthanide oxo-alkoxide derivatives was developed. Heterometallic clusters with the structures [La2Ti4(μ4-O)2(μ3-OEt)2(μ-OEt)8(OEt)6(Cl)2(HOEt)2] (1), [La2Zr2(μ3-O)­(μ-OEt)5(μ-Cl)­(OEt)2(HOEt)4(Cl)4] n (2), [La2Hf2(μ3-O)­(μ-OEt)5(μ-Cl)­(OEt)2(HOEt)4(Cl)4] n (3), [Nd2Ti4(μ4-O)2(μ3-OEt)2(μ-OEt)8(OEt)6(HOEt)2(Cl)2] (4), [Nd4Zr4(μ3-O)2(μ-OEt)10(μ-Cl)4(OEt)8(HOEt)10(Cl)2] (5), and [Nd4Hf4(μ3-O)2(μ-OEt)10(μ-Cl)4(OEt)8(HOEt)10(Cl)2] (6) were synthesized via the reaction of a metallocene dichloride, Cp2M′Cl2 (where M′ = Ti, Zr, and Hf), and metallic lanthanum or neodymium in the presence of excess ethanol. This procedure gave crystalline precursors with molecular stoichiometries suitable for obtaining group 4–lanthanide oxide materials. Compounds 1–6 were examined by analytical and spectroscopic techniques and single-crystal X-ray diffraction. The magnetic properties of 5 and 6 were investigated by using direct and alternating current (dc and ac) susceptibility measurements. The results indicated weak antiferromagnetic interactions between NdIII ions and a field-supported slow magnetic relaxation. Lanthanum–titanium compound 1 decomposed at 950 °C to give the perovskite compound La0.66TiO3 and small amounts of rutile TiO2. Under the same conditions, 4 decomposed to give a mixture of Nd4Ti9O24 and Nd0.66TiO3. When 4 was calcined at 1300 °C, decomposition of Nd4Ti9O24 to Nd0.66TiO3 and TiO2 was observed. Calcination of 2, 3, 5, and 6 at 950–1500 °C led to the selective formation of heterometallic La2Zr2O7, La2Hf2O7, Nd2Zr2O7, and Nd2Hf2O7 phases, respectively.

Heterometallic Rare-Earth Complexes: A Review on Magnetism, Catalysis and Transformation to Nanomaterials

“…Recently Sobota and coworkers reported the synthesis of heterometallic oxo-alkoxides by the reaction of metallic lanthanides with divalent transition metal chlorides MCl2 (M II = Mn II , Ni II or Co II ) or group 4 metallocene dichlorides Cp2MCl2 (where M IV = Ti IV , Zr IV , Hf IV ), using 2-methoxy ethanol or ethanol as solvents and reagents [30,31]. The reaction of RECl3 with the molar excess of alkaline or alkaline earth ligand precursors is used as the main method for synthesizing heterometallic rare earth -group 1/group 2 complexes [32,33].…”

Heterometallic 3d–4f Alkoxide Precursors for the Synthesis of Binary Oxide Nanomaterials

“…Recently, we reported a method for the synthesis of functional nanomaterials, i.e., La 0.66 TiO 3 , Nd 0.66 TiO 3 , La 2 Zr 2 O 7 , La 2 Hf 2 O 7 , Nd 2 Zr 2 O 7 , and Nd 2 Hf 2 O 7 , by thermolysis of the group-4 lanthanide oxo-alkoxides [Ln 2 Ti 4 (μ 4 -O) 2 ­(μ 3 -OEt) 2 ­(μ-OEt) 8 ­(OEt) 6 ­(HOEt) 2 Cl 2 ] (Ln = La, Nd); [La 2 M′ 2 (μ 3 -O)­(μ-OEt) 5 ­(μ-Cl)­(OEt) 2 ­(HOEt) 4 Cl 4 ] n ; and [Nd 4 M′ 4 (μ 3 -O) 2 ­(μ-OEt) 10 ­(μ-Cl) 4 (OEt) 8 ­(HOEt) 10 Cl 2 ] (M′ = Zr, Hf) …”