Probing Phase Evolutions of Au-Methyl-Propyl-Thiolate Self-Assembled Monolayers on Au(111) at the Molecular Level

Abstract

A self-assembled monolayer (SAM) consisting of a mixture of CHS-Au-SCH, CHS-Au-S(CH)CH, and CH(CH)S-Au-S(CH)CH was studied systematically using scanning tunneling microscopy and density functional calculations. We find that the SAM is subjected to frequent changes at the molecular level on the time scale of ∼minutes. The presence of CHS or CHS-Au as a dissociation product of CHS-Au-SCH plays a key role in the dynamical behavior of the mixed SAM. Slow phase separation takes place at room temperature over hours to days, leading to the formation of methyl-thiolate-rich and propyl-thiolate-rich phases. Our results provide new insights into the chemistry of the thiolate-Au interface, especially for ligand exchange reaction in the RS-Au-SR staple motif.

Diffusion of Au(CH3S)2 on Au(111) Observed with the Scanning Tunneling Microscope

“…It may be of interest to examine this transition in greater detail, as it may be that the transition to the 2D gas phase occurs when the Au­(CH 3 S) 2 molecules themselves begin to break up. There is clear evidence that the RS–Au–SR staple breaks into RS and Au–SR at RT from surface reactions involving thiols of different alkane chain lengths. , …”

“…There is clear evidence that the RS−Au−SR staple breaks into RS and Au−SR at RT from surface reactions involving thiols of different alkane chain lengths. 14,15 4. CONCLUSIONS In summary, a number of interesting dynamical processes have been studied in the low-coverage row phase of CH 3 S−Au− SCH 3 on Au(111).…”

Antifouling Studies of Unsymmetrical Oligo(ethylene glycol) Spiroalkanedithiol Self-Assembled Monolayers

“…Recently, we reported that "conflicted" SAM-based interfaces generated from bidentate spiroalkanedithiols possessing mixed hydrocarbon and fluorocarbon tailgroups exhibit enhanced protein resistance when compared to SAMs generated from their single-component monodentate counterparts [41]. Moreover, the generation of SAMs from dithiol-based adsorbates permits studies of the behavior and properties of interfaces consisting of homogeneously mixed disparate chemical species [38][39][40][41] that would typically phase-separate to form surfaces having patches of single-component domains [42][43][44][45][46].…”

Revealing the Interplay Between Covalent and Non-Covalent Interactions Driving the Adsorption of Monosubstituted Thiourea Derivatives on the Au(111) Surface

“…[1][2][3][4] The strong Au-S chemical affinity has been used to design different molecule-metal systems from the adsorption of organosulphur compounds on gold surfaces, specially the Au(111) surface. [5][6][7] In particular, when this kind of compounds present π delocalized electrons, they exhibit various interesting functionalities (e.g. photochromism, magnetism, etc.…”

“…Adsorption of organosulfur compounds on gold surfaces have drawn a great interest in fields such as single-molecule junctions, self-assembly and electronic devices. − The strong Au–S chemical affinity has been used to design different molecule–metal systems from the adsorption of organosulfur compounds on gold surfaces, specially the Au(111) surface. − In particular, when these compounds present π-delocalized electrons, they exhibit various interesting functionalities (e.g., photochromism, magnetism, etc. ), which make them ideal active components to build up nanodevices. − However, despite the strength of Au–S bond, the geometry of molecules adsorbed on metal surfaces also depends on non-covalent interactions like the host–guest interactions, electrostatic interactions and metal–ligand interactions. , The latter are closely related to the functionality of the molecular headgroup.…”