Molecular-Scale Surface Chemistry of a Common Metal Nanoparticle Capping Agent: Triphenylphosphine on Au(111)

Abstract

Phosphine-stabilized Au clusters have been extensively studied and are used in various applications due to their unique structural, catalytic, and electronic properties. Triphenylphosphine (PPh(3)) is a key stabilizing ligand in the synthesis of Au nanoclusters. Despite its intense use in nanoparticle synthesis protocols, little is known regarding its surface chemistry, monolayer structure, density, and packing arrangement, all of which are important descriptors of functionality. Here, in contrast to sparse earlier investigations, we report that PPh(3) forms very ordered structures on Au(111). Atomic-scale imaging reveals that monolayer formation is accompanied by a partial lifting of the Au(111) surface reconstruction and ejection of extra Au atoms in the surface layer. Interestingly, these atoms are trapped and stabilized as two-dimensional Au nanoislands within the molecular layer. This behavior is in contrast to thiols, also common capping agents, which tend to remove Au atoms beyond those extra atoms present in the native reconstruction and form vacancy islands on the surface. Our data illustrate PPh(3)'s milder reactivity and reveal a new picture of its packing structure. These results shed new light on the surface chemistry of this important ligand for organic, organometallic, and nanoparticle synthesis.

A Flexible Caterpillar‐Like Gold Nanoparticle Assemblies with Ultrasmall Nanogaps for Enhanced Dual‐Modal Imaging and Photothermal Therapy

“…In this study, we used an ethanol solution of 2‐naphthalenthiol (Nap) for the surface‐mediating assembly of Cit‐AuNPs (Scheme ). The thiol of Nap can effectively disturb the citrate anion coordination on the surface of Cit‐AuNPs through adsorption of thiol on the surface (via AuS bond) and simultaneous transfer of the thiol protons to uncoordinated CitCOO groups to form CitCOOH, and the ethanol as an organic solvent provided an important driving force to boost the thiol modification …”

Substrate, Molecular Structure, and Solvent Effects in 2D Self-Assembly via Hydrogen and Halogen Bonding

“…85−88 Triphenylphosphine molecules, for instance, produce an average herringbone separation 50% larger than pristine gold. 89 Since the gold surface reconstruction is partially lifted upon molecular adsorption it cannot be used to reliably calibrate the images, hence the experimental uncertainties are larger than the previous systems (the attempted calibration of the data on Au(111) is discussed in the SI).…”

The interplay of covalency, hydrogen bonding, and dispersion leads to a long range chiral network: The example of 2-butanol

“…Furthermore, in rare cases, a single core tetrameric structure is incomplete and its effect on the square network within a domain or at the edge of an island is evident as it causes a disruption in the square pattern, as shown in investigate the interaction of 2-BuOH with the surface itself we measured the spacing of the herringbone reconstruction which has shown to be a useful guide for the interaction strength of weakly adsorbed molecules. [22][23][24][25][54][55][56] On the clean Au surface, the herringbone spacing is 6.3 nm. 41 Measurements of the herringbones visible under the 2-BuOH networks indicate that they have a spacing of 6.4 ± 0.4 nm, which shows that the herringbone reconstruction remains unperturbed.…”