Spontaneous Breaking and Remaking of the RS–Au–SR Staple in Self-assembled Ethylthiolate/Au(111) Interface

Abstract

The stability of self-assembled RS-Au-SR (R = CH 2 CH 3) /Au(111) interface at room temperature has been investigated using scanning tunneling microscopy (STM) in conjunction with density functional theory (DFT) and MD calculations. The RS-Au-SR staple, also known as Au-adatom-dithiolate (AAD), assembles into staple rows along the [112] direction. STM imaging reveals that while the staple rows are able to maintain a static global structure, individual staples within the row are subject to constant breaking and remaking of the Au-SR bond. The C 2 S-Au-SC 2 /Au(111) interface is under dynamic equilibrium and it is far from rigid. DFT/MD calculations show that a transient RS-Au-Au-SR complex can be formed when a free Au atom is added to the RS-Au-SR staple. The relative high reactivity of the RS-Au-SR staple at room temperature could explain the reactivity of thiolateprotected Au nano-clusters such as their ability to participate ligand-exchange and intercluster reactions.

Shedding Light on the Interfacial Structure of Low-Coverage Alkanethiol Lattices

“…Au 144 (RS) 60 disintegration provides an excess of Au adatoms and implies the transfer of mobile RS-Au species to the substrate. 31,32 Hence, we have studied the adsorption of (Au-RS) 2 units in polymeric-like structures forming H-H and H-T phases. Taking as a starting point models X and XII, which exhibit similar E b , an extra Au adatom was added to the respective unit cells forming the corresponding polymeric Another strategy to retain the optimal S−Au adatom distances in the polymeric structure is to place the polymeric species along the [11̅ 0] direction instead of along the [12̅ 1] direction like in models XIII and XIV.…”

Anchoring and packing of self-assembled monolayers ofsemithio-bambusurils on Au(111)

“…via a Au adatom. 39 This type of bonding could be a result of an oxidized sulfur atom 37 of high conformational strain, which leads to weakening of the Au-S bond. 40 When Au adatom bonding occurs, the Au-Au contact is weakened, which makes the Au-S complex more mobile and leads to a reduced intensity in the STM images.…”

Unraveling the Causes of the Instability of Aun(SR)x Nanoclusters on Au(111)

“…52 The RS-Au-SR opening by AuNC interaction with the step edge leads to the NC shell's weakness and exposes the Au core atoms to the environment. Thus, AuNCs' components start to disintegrate, leading first to the Au-SR 53 and Au adatoms on the surface (Figure 4b), and finally, to RS-Au-SR staples and Au islands. The fact that this process is restricted to the NC-step edge interaction besides with the high cohesive energy of this cluster results in a low population of RS-Au-SR, which accordingly accommodate in LD phases (θ SR = 1/8) and a relatively small number of Au islands (Figure 4c).…”