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 (μ 3 -OR) 4 ] (R = i Pr ( 1a ), t Bu ( 1b ), Cy Hex ( 1c )) having a cubane-shaped LiMg 3 O 4 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(μ 3 -OR)] 4 ( R = i Pr ( 2a ), t 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, 7 Li MAS NMR 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.