Self-Assembled Monolayers of Aromatic Tellurides on (111)-Oriented Gold and Silver Substrates

Abstract

Self-assembled monolayers (SAMs) formed from bis(4‘-methylbiphenyl-4-yl) ditelluride (BBPDTe) precursors on Au(111) and Ag(111) substrates were characterized by high-resolution X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy. BBPDTe was found to adsorb dissociatively on both substrates, resulting in the formation of well-defined, densely packed, and ordered BPTe SAMs, with a larger molecular inclination, a lower packing density, and inferior crystallinity on Au than on Ag. However, both BPTe/Au and BPTe/Ag were not stable under ambient conditions but underwent rapid autoxidation, which affected exclusively the tellurolate headgroups. The BPTe molecules in the oxidized films remained, however, bound to the substrate by the terminal O atoms coordinated to the Te moieties, and the quality of the films, given by parameters such as packing density, degree of orientational order, and average tilt angle of the SAM constituents, was not noticeably affected by the autoxidation. In addition, the BPTe SAMs were compared with the analogous thiol- and selenol-based systems, and common tendencies for the different chalcogen headgroups, ranging from Te to O, were derived.

Zwitterionic dithiocarboxylates derived from N-heterocyclic carbenes: coordination to gold surfaces

“…The imidazole tilt angle found for this SAMs is slightly higher than the corresponding tilt angles found for related aromatic SAMs on gold, such as, for example, SAMs based on biphenyl (Θ≈23°), para -terphenyl (Θ≈20°) or anthracene (Θ≈23°) backbones, 29 but it is close to orientations observed for biphenyl tellurolate on gold (Θ≈28°). 30 The molecular alignment is superior to SAMs with short aromatic backbones comparable with 2 + –CS 2 − , for example benzene-thiols on gold, which have been shown to form mostly disordered layers. 29 …”

Modification of biphenylselenolate monolayers by low‐energy electrons

“…In fact, there are experimental data showing that organoselenols bind stronger to coinage metals than organothiols. In particular, this is evidenced by displacement and competitive adsorption studies performed with biphenyl diselenide and biphenyl disulfide [46], detailed studies of alkaneselenol and alkanethiol SAMs using XPS [34], and synchrotron-based high-resolution XPS studies of the adsorbate induced shift of the substrate emission BE in different thiol-and selenolbased SAMs [35,36]. Theoretical calculations of the adsorption energy performed for the entire set of chalcogenates on coinage metals further support these results [75,76].…”

Thiolate versus Selenolate: Structure, Stability, and Charge Transfer Properties

“…Accordingly, the suitable candidates are selenium and tellurium, with a clear preference for the former element in view of the limited stability of tellurium-based monolayers. 23 Along these lines, a variety of aliphatic and aromatic SAMs with the selenol headgroup has been prepared on Au(111) and Ag(111) substrates and studied to different extent. 19, The quality of these SAMs was in most cases comparable or even superior to that of the monolayers prepared from the thiol analogues.…”