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Heteroatom Effects on Quantum Interference in Molecular Junctions: Modulating Antiresonances by Molecular Design

O’Driscoll, Luke J.; Sangtarash, Sara; Xu, Wei; Daaoub, Abdalghani; Hong, Wenjing; Sadeghi, Hatef; Bryce, Martin R.

Heteroatom Effects on Quantum Interference in Molecular Junctions: Modulating Antiresonances by Molecular Design Thumbnail


Authors

Sara Sangtarash

Wei Xu

Abdalghani Daaoub

Wenjing Hong

Hatef Sadeghi



Abstract

Controlling charge transport through molecular wires by utilizing quantum interference (QI) is a growing topic in single-molecular electronics. In this article, scanning tunneling microscopy-break junction techniques and density functional theory calculations are employed to investigate the single-molecule conductance properties of four molecules that have been specifically designed to test extended curly arrow rules (ECARs) for predicting QI in molecular junctions. Specifically, for two new isomeric 1-phenylpyrrole derivatives, the conductance pathway between the gold electrodes must pass through a nitrogen atom: this novel feature is designed to maximize the influence of the heteroatom on conductance properties and has not been the subject of prior investigations of QI. It is shown, experimentally and computationally, that the presence of a nitrogen atom in the conductance pathway increases the effect of changing the position of the anchoring group on the phenyl ring from para to meta, in comparison with biphenyl analogues. This effect is explained in terms of destructive QI (DQI) for the meta-connected pyrrole and shifted DQI for the para-connected isomer. These results demonstrate modulation of antiresonances by molecular design and verify the validity of ECARs as a simple “pen-and-paper” method for predicting QI behavior. The principles offer new fundamental insights into structure–property relationships in molecular junctions and can now be exploited in a range of different heterocycles for molecular electronic applications, such as switches based on external gating, or in thermoelectric devices.

Citation

O’Driscoll, L. J., Sangtarash, S., Xu, W., Daaoub, A., Hong, W., Sadeghi, H., & Bryce, M. R. (2021). Heteroatom Effects on Quantum Interference in Molecular Junctions: Modulating Antiresonances by Molecular Design. Journal of Physical Chemistry C, 125(31), 17385-17391. https://doi.org/10.1021/acs.jpcc.1c04242

Journal Article Type Article
Online Publication Date Aug 2, 2021
Publication Date 2021
Deposit Date Aug 24, 2021
Publicly Available Date Aug 24, 2021
Journal The Journal of Physical Chemistry C
Print ISSN 1932-7447
Electronic ISSN 1932-7455
Publisher American Chemical Society
Peer Reviewed Peer Reviewed
Volume 125
Issue 31
Pages 17385-17391
DOI https://doi.org/10.1021/acs.jpcc.1c04242

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