Gold−Sulfur Interactions in Alkylthiol Self-Assembled Monolayers Formed on Gold Nanoparticles Studied by Solid-State NMR

Current understanding of the structure, phase transitions and dynamics of self-assembled monolayers on two- and three-dimensional surfaces

“…These are attributed to the discontinuity in the diamagnetic susceptibility at the Auhydrocarbon interface and residual dipolar interactions in alkanethiolate monolayers. Badia et al compared the adsorption of thiols on a cluster surface with that of Au(1) alkyl thiolates and found that the chemisorbed species on the gold nanoparticle surface is a thiolate, not a disulphide [200]. They observed a line broadening of the C 1 and C 2 sites, which is explained as due to the chemical shift distribution resulting from the different adsorption sites and/or non-spherical particle shapes.…”

Structure and dynamics of monolayers on planar and cluster surfaces

“…These are attributed to the discontinuity in the diamagnetic susceptibility at the Au-hydrocarbon interface and residual dipolar interactions in alkanethiolate monolayers. Badia et al compared the adsorption of thiols on a cluster surface with Au(1) alkyl thiolates and found that the chemisorbed species on the gold nanoparticle surface is a thiolate, not a disulfide [69]. They observed a line broadening of the C 1 and C 2 sites, which is explained as due to the chemical shift distribution resulting from the different adsorption sites and/or nonspherical particle shapes.…”

Monolayer Protected Clusters of Gold and Silver

“…Both 1 H and 13 C NMR spectra of MPCs exhibit very significant peak broadening, the origin of which is still debated. The signals from the nuclei closest to the gold core are those that are most broadened, which is probably due to a combination of intermolecular interactions within the ligand shell, similar to those responsible for peak broadening in solid-state materials, and a distribution of chemical shifts due to the heterogeneity of binding sites in a mixture of clusters of many different sizes and shapes [41,69,71].…”

“…The results of these investigations can broadly be summarized by the notion that the ligand shell resembles a self-assembled monolayer of thiolate molecules on a planar gold surface except for its higher packing density. For this reason MPCs have also been described as ªmonolayers in three dimensionsº and have served as a model system for spectroscopic studies, in particular NMR, which would have been impossible using planar SAMs given the extremely small amount of material present in a monolayer on a macroscopic, planar surface [41,69,71]. Both 1 H and 13 C NMR spectra of MPCs exhibit very significant peak broadening, the origin of which is still debated.…”