Oligo(aryleneethynylene)s with Terminal Pyridyl Groups: Synthesis and Length Dependence of the Tunnelling to Hopping Transition in Single-Molecule Conductances

Zhao, Xiaotao; Huang, Cancan; Gulcur, Murat; Batsanov, Andrei S.; Baghernejad, Masoud; Hong, Wenjing; Bryce, Martin R.; Wandlowski, Thomas

Abstract

The synthesis is reported of a new series of oligo(aryleneethynylene) (OAE) derivatives of up to ca. 6 nm in molecular length (OAE9) using iterative Pd-mediated Sonogashira cross-coupling methodology. The oligo-p-phenyleneethynylene cores of the molecular wires are functionalized at both termini with pyridyl units for attachment to gold leads. The molecular structures determined by single-crystal X-ray analysis are reported for OAE4, OAE5, OAE7, and OAE8a. The charge transport characteristics of derivatives OAE3–OAE9 in single-molecular junctions have been studied using the mechanically controlled break junction technique. The data demonstrate that the junction conductance decreases with increasing molecular length. A transition from coherent transport via tunneling to a hopping mechanism is found for OAE wires longer than ca. 3 nm.

Citation

Zhao, X., Huang, C., Gulcur, M., Batsanov, A. S., Baghernejad, M., Hong, W., …Wandlowski, T. (2013). Oligo(aryleneethynylene)s with Terminal Pyridyl Groups: Synthesis and Length Dependence of the Tunnelling to Hopping Transition in Single-Molecule Conductances. Chemistry of Materials, 25(21), 4340-4347. https://doi.org/10.1021/cm4029484

• Journal Article Type: Article
• Publication Date: Nov 12, 2013
• Deposit Date: Nov 24, 2014
• Publicly Available Date: Nov 26, 2014
• Journal: Chemistry of Materials
• Print ISSN: 0897-4756
• Electronic ISSN: 1520-5002
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 25
• Issue: 21
• Pages: 4340-4347
• DOI: https://doi.org/10.1021/cm4029484
• Keywords: Molecular electronics, Synthesis, Oligomer, Oligo(aryleneethynylene), Single-molecule conductance, Tunneling, Hopping.
• Public URL: https://durham-repository.worktribe.com/output/1419430