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Side‐Group‐Mediated Mechanical Conductance Switching in Molecular Junctions
Author(s) -
Ismael Ali Khalid,
Wang Kun,
Vezzoli Andrea,
AlKhaykanee Mohsin K.,
Gallagher Harry E.,
Grace Iain M.,
Lambert Colin J.,
Xu Bingqian,
Nichols Richard J.,
Higgins Simon J.
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201709419
Subject(s) - conductance , molecular electronics , molecule , alkyl , conjugated system , electrochemistry , bipyridine , electrode , modulation (music) , materials science , chemical physics , molecular switch , chemistry , nanotechnology , crystallography , polymer , condensed matter physics , physics , crystal structure , organic chemistry , acoustics
A key target in molecular electronics has been molecules having switchable electrical properties. Switching between two electrical states has been demonstrated using such stimuli as light, electrochemical voltage, complexation and mechanical modulation. A classic example of the latter is the switching of 4,4′‐bipyridine, leading to conductance modulation of around 1 order of magnitude. Here, we describe the use of side‐group chemistry to control the properties of a single‐molecule electromechanical switch, which can be cycled between two conductance states by repeated compression and elongation. While bulky alkyl substituents inhibit the switching behavior, π‐conjugated side‐groups reinstate it. DFT calculations show that weak interactions between aryl moieties and the metallic electrodes are responsible for the observed phenomenon. This represents a significant expansion of the single‐molecule electronics “tool‐box” for the design of junctions with electromechanical properties.