Unconventional Single-Molecule Conductance Behavior for a New Heterocyclic Anchoring Group: Pyrazolyl

Herrer, I Lucia, Ismael, Ali K, Milan, David C ORCID: 0000-0002-2077-7920, Vezzoli, Andrea ORCID: 0000-0002-8059-0113, Martin, Santiago, Gonzalez-Orive, Alejandro, Grace, Iain, Lambert, Colin, Serrano, Jose L, Nichols, Richard J ORCID: 0000-0002-1446-8275
et al (show 1 more authors) (2018) Unconventional Single-Molecule Conductance Behavior for a New Heterocyclic Anchoring Group: Pyrazolyl. JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 9 (18). pp. 5364-5372.

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Electrical conductance across a molecular junction is strongly determined by the anchoring group of the molecule. Here we highlight the unusual behavior of 1,4-bis(1H-pyrazol-4-ylethynyl)benzene that exhibits unconventional junction current versus junction-stretching distance curves, which are peak-shaped and feature two conducting states of 2.3 × 10<sup>-4</sup> G<sub>0</sub> and 3.4 × 10<sup>-4</sup> G<sub>0</sub>. A combination of theory and experiments is used to understand the conductance of single-molecule junctions featuring this new anchoring group, i.e., pyrazolyl. These results demonstrate that the pyrazolyl moiety changes its protonation state and contact binding during junction evolution and that it also binds in either end-on or facial geometries with gold contacts. The pyrazolyl moiety holds general interest as a contacting group, because this linkage leads to a strong double anchoring of the molecule to the gold electrode, resulting in enhanced conductance values.

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 18 Sep 2018 08:17
Last Modified: 19 Jan 2023 01:17
DOI: 10.1021/acs.jpclett.8b02051
Open Access URL: http://doi.org/10.1021/acs.jpclett.8b02051
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3026429