Theoretical insights into the adsorption of neutral, radical and anionic thiophenols on gold(111)

Abstract

The interaction of thiol and thiolate containing molecules with gold (S-Au) has gained increasing interest because of its applications in molecular electronic devices and catalysis. In this context, the enhanced conductivity of thiophenol compared to alkanethiol represents an opportunity to develop more sensitive and selective gold-based devices by incorporating molecules with the aryl-thiol moiety into their structures. As has been proposed earlier, the thiol moiety is deprotonated after binding to gold, hence, we present here a comparative study of the S-Au bond strength between several neutral and deprotonated aromatic-sulfur systems in their anionic and radical forms with a detailed description of the nature of this interaction. The study was performed by means of computational chemistry methods, using a cluster of 42 Au atoms as a model of the Au(111) surface that allowed us to provide new chemical insights to control the S-Au interface interaction strength. Our results revealed that the thiophenols-gold interaction is mainly dispersive where the interaction energies range between 31 and 43 kcal mol(-1). The radical and anionic thiophenolates-gold interaction increases due to a strong charge transfer character, depicting interaction energies in the range of 50 to 55 kcal mol(-1) and 62 to 92 kcal mol(-1), respectively. These results suggest that for the anionic thiophenolate the binding strength can be tailored according to the electron-donor capabilities of the ligand which in turn can be finely tuned by several substituents. Our results are of possible impact for the design of new devices.

Measurement and understanding of single-molecule break junction rectification caused by asymmetric contacts

“…5 and Ref. 30. As expected, the RR for symmetric junctions stays around 1 across the whole bias range, indicating a nearly equal current under positive and negative bias.…”

“…Binding energies of contact bonds in our study have been calculated to be 0.37 eV for Au-NH 2 and 1.60 eV for Au-SH. 18,29,30 It is believed that a higher binding energy implies a stronger coupling between the molecule and the electrode, 18, 29 indicating a much stronger coupling for Au-SH than for Au-NH 2 . Theoretical calculations 10,19 suggested that factors like the local bonding length and junction elongation and tilt would not be the major effect within our bias window, which rules out the concerns on the related influence caused by these factors.…”

Noncovalent interactions in inorganic supramolecular chemistry based in heavy metals. Quantum chemistry point of view

“…We have used the DFT methodology at the TPSS and TPSS‐D3 levels. The study was performed by means of computational chemistry methods, using a cluster of 42 Au atoms as a model for the Au(111) surface that allowed us to provide new chemical insights to control the S–Au interfaces interaction strength (see Figure G) . Our results revealed that the thiophenols–gold interaction is mainly dispersive where the interaction energies range between 130 and 180 kJ/mol (see Table ).…”

A comparative study between post-Hartree–Fock methods and density functional theory in closed-shell aurophilic attraction

“…Other reasons for interest in these interactions are due to different characteristics of gold such as the electronic structure of gold nanoparticles, gold nanoparticle-ligand interactions, the coordination chemistry of gold, gold clusters, and gold-catalyzed organic transformations [22][23][24][25][26][27][28][29][30]. Moreover, a significant number of studies have discussed the aurophilic interactions coexisting with H-bonding, M-p or p-p attractions, all of which can participate in generating extended, supramolecular structures and nanochemistry [31][32][33][34][35].…”