[Au5Mes5]: improved gram-scale synthesis and its use as a convenient precursor for halide-free supported gold nanoparticles

Abstract

A simple one-step and gram-scale synthesis of [Au₅Mes₅] from AuCl₃ was developed, and this molecular precursor was used to generate Au nanoparticles on SiO₂ and Al₂O₃. While [Au₅Mes₅] does not react with surface silanols and is only physisorbed, its incipient wetness impregnation followed by H₂ treatment leads to a narrow size distribution of 1.4 nm Au nanoparticles. In contrast, [Au₅Mes₅] reacts with partially dehydroxylated Al₂O₃ to directly yield 1 nm Au nanoparticles along with adsorbed species. A subsequent treatment under hydrogen leads to a narrow size distribution of smaller 0.8 nm Au particles.