The Role of Oligomeric Gold-Thiolate Units in Single Molecule Junc-tions of Thiol-Anchored Molecules

Using the break junction (BJ) technique we show that Au(RS)2 units play a significant role in thiol-terminated molecular junctions formed on gold. We have studied a range of thiol-terminated compounds, either with the sulfur atoms in direct conjugation with a phenyl core, or bonded to saturated meth...

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Bibliographic Details
Published in:arXiv.org 2018-03
Main Authors: Leary, Edmund, Zotti, Linda A, Delia, Miguel, Márquez, Irene R, Palomino-Ruiz, Lucía, Cuerva, Juan Manuel, Rubio-Bollinger, Gabino, González, M Teresa, Agrait, Nicolás
Format: Article
Language:English
Subjects:
Anchors
Conjugation
Gold
Nanoparticles
Organic chemistry
Resistance
Online Access:Get full text
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Summary:Using the break junction (BJ) technique we show that Au(RS)2 units play a significant role in thiol-terminated molecular junctions formed on gold. We have studied a range of thiol-terminated compounds, either with the sulfur atoms in direct conjugation with a phenyl core, or bonded to saturated methylene groups. For all molecules we observe at least two distinct groups of conductance plateaus. By a careful analysis of the length behavior of these plateaus, comparing the behavior across the different cores and with methyl sulfide anchor groups, we demonstrate that the lower conductance groups correspond to the incorporation of Au(RS)2 oligomeric units at the contacts. These structural motifs are found on the surface of gold nanoparticles but they have not before been shown to exist in molecular-break junctions. The results, while exemplifying the complex nature of thiol chemistry on gold, moreover clarify the conductance of 1,4-benzenedithiol on gold. We show that true Au-S-Ph-S-Au junctions have a relatively narrow conductance distribution.
ISSN:2331-8422
DOI:10.48550/arxiv.1803.07411