Molecular Heterobimetallic Approach to Li-Containing MgO Nanoparticles with Variable Li-Concentrations Using Lithium-Methylmagnesium Alkoxide Clusters

Facile synthesis and characterization of the first heterobimetallic lithium-methylmagnesium-alkoxide clusters [Li(thf)(MeMg)(3)(mu(3)-OR)(4)] (R = Pr-i (1a), 'Bu (1b), (Cy)Hex (1c)) having a cubane-shaped LiMg3O4 core is reported. They have been employed as molecular single-source precursors for bottom up synthesis of Li-containing MgO nanoparticles with varying Li-concentrations. This can be achieved by solid state decomposition of homogeneous mixtures of the latter compounds (1a-c) with the corresponding homometallic alkylmagnesium alkoxide cubanes [MeMg(mu(3)-OR))(4) (R = Pr-i (2a), 'Bu (2b), (Cy)Hex (2c)). Characterization of the final obtained materials was accomplished by a combination of different analytical techniques such as TGA, PXRD, TEM, Raman spectroscopy, Li-7 MAS NM R spectroscopy, elemental analysis, and nitrogen adsorption. The different parameters that affect the composition and morphology of the Li-containing MgO nanoparticles have been examined. It has been found that Li concentrations up to 1 wt % lead to well-defined crystalline materials, where the Li ions are likely incorporated in the magnesium oxide lattice, whereas higher Li concentrations afford less-ordered materials, which consist of additional crystalline and amorphous phases.