2,7- and 4,9-Dialkynyldihydropyrene Molecular Switches: Syntheses, Properties, and Charge Transport in Single-Molecule Junctions

Max Roemer, Angus Gillespie, David Jago, David Costa-Milan, Jehan Alqahtani, Juan Hurtado-Gallego, Hatef Sadeghi, Colin J. Lambert, Peter R. Spackman, Alexandre N. Sobolev, Brian W. Skelton, Arnaud Grosjean, Mark Walkey, Sven Kampmann, Andrea Vezzoli, Peter V. Simpson, Massimiliano Massi, Inco Planje, Gabino Rubio-Bollinger, Nicolás AgraïtSimon J. Higgins, Sara Sangtarash, Matthew J. Piggott, Richard J. Nichols, George A. Koutsantonis

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


This paper describes the syntheses of several functionalized dihydropyrene (DHP) molecular switches with different substitution patterns. Regioselective nucleophilic alkylation of a 5-substituted dimethyl isophthalate allowed the development of a workable synthetic protocol for the preparation of 2,7-alkyne-functionalized DHPs. Synthesis of DHPs with surface-anchoring groups in the 2,7- and 4,9-positions is described. The molecular structures of several intermediates and DHPs were elucidated by X-ray single-crystal diffraction. Molecular properties and switching capabilities of both types of DHPs were assessed by light irradiation experiments, spectroelectrochemistry, and cyclic voltammetry. Spectroelectrochemistry, in combination with density functional theory (DFT) calculations, shows reversible electrochemical switching from the DHP forms to the cyclophanediene (CPD) forms. Charge-transport behavior was assessed in single-molecule scanning tunneling microscope (STM) break junctions, combined with density functional theory-based quantum transport calculations. All DHPs with surface-contacting groups form stable molecular junctions. Experiments show that the molecular conductance depends on the substitution pattern of the DHP motif. The conductance was found to decrease with increasing applied bias.
Original languageEnglish (US)
JournalJournal of the American Chemical Society
StatePublished - Jun 29 2022
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2022-07-06
Acknowledgements: This research was supported under the Australian Research Council’s Discovery Projects funding scheme (Project Numbers DP 150104117 and DP 200101659). The authors acknowledge the facilities and the scientific and technical assistance of the Australian Microscopy and Microanalysis Research Facility at the Centre for Microscopy, Characterisation, and Analysis, The University of Western Australia, a facility funded by the University, State and Commonwealth Governments. D.C.-M. gratefully acknowledges the School of Physical Sciences Postdoctoral Development Award of the University of Liverpool for financial support. The work in Warwick was funded by UKRI Future Leaders Fellowship Number MR/S015329/2 and Leverhulme Trust Early Career Fellowship Number ECF-2018-375. A.V. thanks the Royal Society for funding (URF\R1\191241). The work in King Khalid University used the resources of the Supercomputing Laboratory at King Abdullah University of Science & Technology (KAUST) in Thuwal, Saudi Arabia.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.

ASJC Scopus subject areas

  • Biochemistry
  • Colloid and Surface Chemistry
  • General Chemistry
  • Catalysis


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