One-pot synthesis of lithium alkylzinc alkoxo heterocubanes with a LiZn3O4 core as suitable organometallic precursors for Li-containing ZnO nanocrystals

A convenient and efficient synthesis of the stable monolithium alkylzinc alkoxo cubanes {Li(thf)(RZn)(3)(OR)(4)} [R=Me, R'= Pr-i(1), Bu-t(2); R=Et, R'= Pr-i(3), Bu-t(4)] is reported. They are well soluble in organic solvents and suitable molecular precursors for the formation of Li-containing ZnO nanoparticles. The compounds are accessible by a convenient one-pot reaction of the respective dialkylzinc with lithium alkoxides in the presence of water and can be isolated as white solids in 35-50% yield. Higher yields (80-85%) for 1 and 3 can be achieved by applying excess (PrOH)-Pr-i instead of H2O as protolysis source. The compounds 1-4 were characterized by elemental analyses, multinuclear NMR and FT-IR spectroscopy, and single-crystal X-ray diffraction analysis (1 and 2). Interestingly, thermal treatment of solutions of 1 and 2, respectively, in anhydrous benzyl alkohol at 190 degrees C yields pure and highly crystalline Li-containing ZnO nanoparticles as evidenced by powder X-ray diffraction analysis (PXRD), Transition Electron Microscopy (TEM), FT-IR and Li-7 MAS NMR spectroscopy.