A one-pot synthesis of oligo(arylene-ethynylene)-molecular wires and their use in the further verification of molecular circuit laws

Naher, Masnun, Gorenskaia, Elena, Moggach, Stephen A, Becker, Thomas, Nichols, Richard J ORCID: 0000-0002-1446-8275, Lambert, Colin J and Low, Paul J
(2022) A one-pot synthesis of oligo(arylene-ethynylene)-molecular wires and their use in the further verification of molecular circuit laws. AUSTRALIAN JOURNAL OF CHEMISTRY, 75 (9). pp. 506-522.

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<jats:p>A convenient two-step, one-pot synthesis of oligo(arylene–ethynylene) (OAE) type molecular wires in yields of up to 70% via in situ desilylation of protected bis(alkynes) Me3SiC≡CArC≡CSiMe3 (Ar = 2,5-thienyl, 1,4-naphthylene, 9,10-anthrylene) and subsequent Sonogashira cross-coupling with S-(4-iodophenyl) ethanethiolate, 4-iodothioanisole, or 5-bromo-3,3-dimethyl-2,3-dihydrobenzo[b]thiophene is described. The in situ desilylation avoids the manipulation of the sensitive terminal dialkynes (HC≡CArC≡CH), whilst the general approach presented has some advantages over alternative synthetic strategies based on coupling of aryl dihalides (XArX) by avoiding the multi-step preparation and purification of the terminal alkynes S-(4-ethynylphenyl) ethanethiolate, 4-ethynylthioanisole and 5-ethynyl 3,3-dimethyl-2,3-dihydrobenzo[b]thiophene. The molecular conductance of the resulting thiolate or thioether functionalised OAE molecular wires has been determined using scanning tunneling microscope break junction (STM-BJ) methods. The trends in molecular conductance do not track simply with the degree of aromaticity of the molecular core despite the rather similar molecular lengths. Rather, the STM-BJ data are better correlated with the nature of the anchor group, highlighting the important role of electrode–molecule coupling on electron transport in a molecular junction. The experimental conductance data are in good agreement with recently described quantum circuit rules, further highlighting the potential for these relationships to be used as predictive tools in molecular electronics research.</jats:p>

Item Type: Article
Uncontrolled Keywords: molecular electronics, molecule-electrode coupling, molecular junction, molecular wire, oligo(phenylene-ethynylene), single-molecule conductance, Sonogashira coupling, STM-break junction
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 13 Sep 2022 13:16
Last Modified: 18 Jan 2023 20:45
DOI: 10.1071/CH21235
Open Access URL: https://www.publish.csiro.au/ch/CH21235
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3164532