A general synthesis strategy for monodisperse metallic and metalloid nanoparticles (In, Ga, Bi, Sb, Zn, Cu, Sn, and Their Alloys) via in situ formed metal long-chain amides

Abstract

We report a facile one-pot synthesis of highly monodisperse nanoparticles (5-30 nm in diameter, 5-10% in standard size distribution) of various metals and metalloids such as In, Sn, Bi, Sb, Ga, Cu, Zn, and their alloys (Cu6Sn5, Cu2Sb, BixSb1-x, etc.) using inexpensive commercial precursors. Several of these metals and alloys had not been previously obtained in the form of uniform nanoparticles. The proposed reaction mechanism has been elucidated with multinuclear (1H, 7Li, 119Sn) NMR spectroscopy combined with DFT and molecular dynamics simulations. Metal chloride is reacted with long-chain primary or secondary amine such as oleylamine and dioctylamine in the presence of a strong Brønsted base that deprotonates the amine and thus promotes the formation of metal long-chain amide. The in situ formed amide is then reduced or thermally decomposed into corresponding metal nanoparticles. This simple methodology eliminates elaborate preparation, storage, and handling of highly reactive, moisture and oxygen sensitive molecular precursors of these metals, while providing a compelling quality of nanomaterials.