title: Facile synthesis of gold icosahedra in an aqueous solution by reacting HAuCl(4) with N-vinyl pyrrolidone.
abstract: Herein we describe a protocol that generates Au icosahedra in high yields by simply mixing aqueous solutions of HAuCl(4) and N-vinyl pyrrolidone. Our mechanistic study reveals that water plays an important role in this synthesis: as a nucleophile, it attacks the gold-vinyl complex, leading to the production of an alcohol-based Au(I) intermediate. This intermediate then undergoes a redox reaction in which Au(I) is reduced to Au(0), leading to the formation of Au atoms and then Au icosahedra of about 18 nm in size at a yield of 94 %, together with a carboxylic acid in the final product. This new protocol has also been employed to prepare multiply twinned nanoparticles of Ag (15-20 nm in size), spherical aggregates (25-30 nm in size) of Pd nanoparticles, and very small nanoparticles of Pt (2 nm in size). Since no organic solvent, surfactant, or polymer stabilizer is needed for all these syntheses, this protocol may provide a simple, versatile, and environmentally benign route to noble-metal nanoparticles having various compositions and morphologies.
authors.affiliation: Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, Missouri 63130, USA.
authors.forename: Mustafa S
authors.initials: MS
authors.lastname: Yavuz
authors.forename: Weiyang
authors.initials: W
authors.lastname: Li
authors.forename: Younan
authors.initials: Y
authors.lastname: Xia
mesh_terms: D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D011760:Pyrrolidinones / Q000737:chemistry*; D012996:Solutions; D014867:Water
chemical_list: D011760:Pyrrolidinones; D012996:Solutions; D014867:Water; D006046:Gold; C042670:N-vinyl-2-pyrrolidinone