Interaction between organic molecules and a gold nanoparticle: a quantum chemical topological analysis

Abstract

The ligands at the surface of a gold nanoparticle (GNP) have a significant influence on the optical and physical properties, that may render different functionalities to the GNP. Therefore, there is a need in understanding the nature of the interaction at atomic resolution in order to allow rational design of GNPs with desired physico-chemical properties. The interaction between Au 79 and a series of small organic molecules has been systematically studied at the quantum mechanical level : methane, methanol, formic acid, hydrogen sulfide, benzene, and ammonia. The reactivity of Au 79 has been first analyzed by performing the condensed Fukui analysis to emphasize that the surface of Au 79 is dominated by electrophilic sites, with higher reactivity at the corner and edge atoms. The net charge transfer flowing from the organic molecules towards Au 79 , comes from the electrophilic behaviour of the GNP. Furthermore, the shape of the frontier molecular orbitals of Au 79 and of the incoming organic molecules has been found to dictate the preferred orientation of the adsorption. Several quantum chemical topological analyses of the electron density have been

Raman spectra and DFT calculations of thiophenol molecules adsorbed on a gold surface

“…For the low-density configuration, the aromatic ring lies parallel to the metallic surface. This result is in accordance with Tandiana et al , 47 who indicated that benzene preferred to adopt a flat configuration on gold nanoparticles. In contrast, when the density is high, the steric hindrance would induce a strongly different orientation of benzene so that the molecule is now oriented vertically to the surface.…”

Characterization of the absorption properties of 5 nm spherical gold nanoparticles functionalized with dodecanothiol and without functionalization with potential therapeutic applications

“…Before irradiation (t = 0) the maxima of the suspensions were found at 534 nm and 540 nm (figures 5(b) and (d)) revealing more intense variations in plasmon frequency relative to the AuNP-ABMA suspensions. These interactions must be associated with adsorption of DCPIP on the NP surface (Tandiana et al 2021). During the first 20 min of irradiation at 532 nm there was a hypsochromic shift of 18 nm from the maximum of the suspension while its intensity decreased > 35% (figures 5(a) and (b)).…”

“…However, in contrast to the irradiation of isolated AuNPf dissolved in toluene (figure 1(c)) in the presence of ABMA and DMSO the λ max showed a slight red shift (4 nm) in the first 10 min of irradiation (figure 6(e)) suggesting the occurrence of changes in the plasmon properties due to: (a) probable aggregation of AuNPf; (b) interactions between ABMA and DMSO, already described (section 3.2.1.). The high electrophilicity of Au NPs alters their surface electron density in the presence of organic molecules affecting λ max (Kamat et al 2002, Tandiana et al 2021. As the irradiation time increased the λ max shifted to blue while observing a remarkable total intensity variation (>60%) and band broadening (figures 6(c) and (e)).…”

In-depth theoretical understanding of the chemical interaction of aromatic compounds with a gold nanoparticle

“…Our previous work on the interaction with a series of small organic molecules has indicated that benzene prefers to adopt a flat configuration (with the aromatic plane interacting parallel to the surface of GNP). 31 This could be attributed to the optimized interaction between the HOMO of benzene and LUMO of GNP, as well as the maximization of dispersion interactions. However, previous studies of aromatic containing compounds deposited on metal surfaces have indicated that the aromatic plane is not always adsorbed in a parallel configuration.…”