Hemilabile Ligands as Mechanosensitive Electrode Contacts

  • Author: Angewandte Chemie International Edition
  • Published Date: 27 September 2019
  • Source / Publisher: Angewandte Chemie International Edition/Wiley-VCH
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA
thumbnail image: Hemilabile Ligands as Mechanosensitive Electrode Contacts

Molecules with a conductance that is "gated" by external stimuli (e.g., light or an external potential) can be useful in molecular electronics. Andrea Vezzoli, Simon J. Higgins, University of Liverpool, UK, Sara Sangtarash, Lancaster University and University of Warwick, UK, Colin J. Lambert. Lancaster University, and colleagues have developed another mode of conductance control. The team designed molecules whose conductance increases sharply upon a change in their binding mode to metal contacts (pictured). This uses a concept known from homogeneous catalysis: the hemilability of bidentate ligands with a strongly and a weakly binding group.

The team designed conjugated molecules ("molecular wires") with (2-methylthio)thiophene units at the end as contacts. These molecular wires can interact with a metal electrode, e.g., a gold substrate. The junction between the thiophene groups and the electrode can be modified using a scanning tunneling microscopy (STM) technique. The team observed conductance changes of up to two orders of magnitude as the junctions were compressed and stretched by moving the microscopy tip.

The researchers explain this observation by additional weak contacts between the thiophene's sulfur atoms and gold electrodes that occur only at short tip–substrate distances, i.e., there is a monodentate→bidentate transition when the distance is reduced. This additional interaction increases the conductance. Building such features into molecules offers a new method to control their electrical properties.


Article Views: 1147

Sign in Area

Please sign in below

Additional Sign In options

Please note that to comment on an article you must be registered and logged in.
Registration is for free, you may already be registered to receive, e.g., the newsletter. When you register on this website, please ensure you view our terms and conditions. All comments are subject to moderation.

Article Comments - To add a comment please sign in

If you would like to reuse any content, in print or online, from ChemistryViews.org, please contact us first for permission and consult our permission guidance prior to making your request

Follow on Facebook Follow on Twitter Follow on YouTube Follow on LinkedIn Follow on Instagram RSS Sign up for newsletters

Magazine of Chemistry Europe (16 European Chemical Societies) published by Wiley-VCH