Structural investigation of Au(111)/butylthiolate adsorption phases

Abstract

The structures of the high-coverage ('standing-up') and low-coverage ('lying-down') phases of butylthiolate on Au(111) have been investigated by a range of experimental methods. Normal incidence X-ray standing waves, photoelectron diffraction and near-edge X-ray absorption fine structure results all identify the local S headgroup site as atop a surface Au atom in a bulk continuation site for both high- and low-coverage phases. Low energy electron diffraction shows the low-coverage phase to have a (12 x radical 3)rect. surface mesh with glide-line symmetry (pmg space group), the long dimension of this mesh being approximately four times the length of the butylthiolate molecule. A structural model is proposed for this phase based on two different enantiomers of an Au-adatom-dithiolate species that is consistent with these results and with recent finding for propylthiolate on this surface using low-temperature scanning tunnelling microscopy (O. Voznyy, J. J. Dubowski, J. T. Yates Jr. and P. Maksymovych, J. Am Chem. Soc., 2009, 131, 12989).

Effect of lattice-gas atoms on the adsorption behaviour of thioether molecules

“…5d, right panel). The superstructure is commensurate with the NiAl lattice, as adjacent molecules are separated by 5.8 and 8.2 Å along the [001] and [1][2][3][4][5][6][7][8][9][10] direction of NiAl(110), corresponding to two unit cells in both cases. The superstructure fills large portions of the metal surface, before a second molecular layer starts growing on the top of the first one.…”

“…The most common feature is a [1][2][3][4][5][6][7][8][9][10]-oriented rod of 13 Å length that exhibits two outer maxima of 1.3 Å apparent height and a central one that is taller by roughly 0.1 Å (Fig. 5b and d).…”

“…Single adsorbates are randomly distributed on the NiAl(110) surface and form only small assemblies of two or three entities at low coverage. In contrast to the BPB, a molecular superstructure develops at higher exposure that comprises [001]-directed chains of [1][2][3][4][5][6][7][8][9][10]-oriented molecules (Fig. 5d, right panel).…”

“…4,6,7 This insight, gained by combined experimental and theoretical efforts, changed the overall perception of the interplay between metal surfaces and a wide range of organic molecules, including alkane-thiolates, thio-phenol and thioether compounds. 1,[8][9][10] Moreover, the ability of organic ligands to coordinate metal adatoms has initiated a completely new research field that focuses on the development of well-ordered metalorganic frameworks. The associated self-organization phenomena open interesting routes to pattern and functionalize metal surfaces and to generate assemblies for molecular electronic devices.…”

Adsorption height alignment at heteromolecular hybrid interfaces

“…Both are directly related to the properties of the first organic layer adsorbing on a metal surface, since these molecules make the electronic contact with the metal, and act as a template for the further growth of the thicker organic films. This has motivated many recent experimental and theoretical studies of the adsorption of small planar molecules on crystalline noble metal surfaces [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”