In this article, we characterized the polymeric gold(I) thiolatesthat precipitated from the intermediate solutions during the synthesis process ofgold nanoparticles (GNPs) by the Brust?Schiffrin two-phase method andinvestigated the formation mechanism of the polymeric gold(I) thiolates. Thesolution 1H NMR confirmed the complete reduction from Au(III) to Au(I) withthe addition of the first two equivalents of thiols, while only the third and fourthequivalents of thiols were found to participate in forming gold(I) thiolates.Gold(I) thiolates, [Au(I)SR]n, precipitated from these solutions were further
characterized by 1H solid-state NMR spectroscopy under fast magic anglespinning (MAS), Raman spectroscopy, and thermogravimetric analysis. Furtherquantitative studies revealed that the composition of [Au(I)SR]n could becontrolled by changing the order of addition of the third and fourth equivalentsof thiols. This work has great significance to better understand the mechanism ofgold nanoparticle formation and thus to tailor the properties of the final products.
